Access and tissue modification systems and methods

ABSTRACT

Described herein are methods and systems for precisely placing and/or manipulating devices within the body by first positioning a guidewire or pullwire. The device to be positioned within the body is coupled to the proximal end of the guidewire, and the device is pulled into the body by pulling on the distal end of the guidewire that extends from the body. The device may be bimanually manipulated by pulling the guidewire distally, and an attachment to a device that extends proximally, allowing control of both the proximal and the distal ends. In this manner devices (and particularly implants such as innerspinous distracters, stimulating leads, and disc slings) may be positioned and/or manipulated within the body. Guidewire exchange systems, devices and methods are also described. A guidewire may be exchanged between different surgical devices and may be releaseably or permanently coupled.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/127,535, filed on May 27, 2008, titled “GUIDEWIRE EXCHANGESYSTEMS TO TREAT SPINAL STENOSIS,” now Publication No.US-2008-0275458-A1; which is a continuation-in-part of U.S. patentapplication Ser. No. 11/251,199, filed on Oct. 15, 2005, titled “DEVICESAND METHODS FOR TISSUE MODIFICATION,” now U.S. Pat. No. 8,192,435; whichclaims the benefit of U.S. Provisional Patent Application No.60/685,190, filed on May 27, 2005, titled “METHODS AND APPARATUS FORSELECTIVE SURGICAL REMOVAL OF TISSUE;” U.S. Provisional PatentApplication No. 60/681,719, filed on May 16, 2005, titled “METHODS ANDAPPARATUS FOR SELECTIVE SURGICAL REMOVAL OF TISSUE;” U.S. ProvisionalPatent Application No. 60/681,864, filed on May 16, 2005, titled“METHODS AND APPARATUS FOR SELECTIVE SURGICAL REMOVAL OF TISSUE;” U.S.Provisional Patent Application No. 60/622,865, filed on Oct. 28, 2004,titled “METHODS AND APPARATUS FOR SELECTIVE SURGICAL REMOVAL OF TISSUE;”and U.S. Provisional Patent Application No. 60/619,306, filed on Oct.15, 2004, titled “METHODS AND APPARATUS FOR THE TREATMENT OF TISSUEIMPINGEMENT IN THE SPINE.” Each of these patent applications is hereinincorporated by reference in their entirety.

U.S. patent application Ser. No. 12/127,535 is also acontinuation-in-part of U.S. patent application Ser. No. 11/468,247,filed on Aug. 29, 2006, titled “TISSUE ACCESS GUIDEWIRE SYSTEM ANDMETHOD,” now U.S. Pat. No. 7,857,813. Each of these patent applicationsis herein incorporated by reference in their entirety.

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/816,729, filed on Jun. 16, 2010, titled “ACCESS AND TISSUEMODIFICATION SYSTEMS AND METHODS,” now Publication No.US-2010-0331883-A1; which is a continuation-in-part of U.S. patentapplication Ser. No. 11/952,934, filed on Dec. 7, 2007, titled “TISSUEREMOVAL DEVICES AND METHODS,” now Publication No. US-2008-0147084-A1,now abandoned; which claims the benefit of U.S. Provisional PatentApplication No. 60/869,070, filed on Dec. 7, 2006, titled “FLEXIBLETISSUE REMOVAL DEVICES AND METHODS.”

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 12/637,447,filed on Dec. 14, 2009, titled “DEVICES AND METHODS FOR TISSUEMODIFICATION,” now Publication No. 2010-0094231-A1; which is acontinuation of U.S. patent application Ser. No. 12/428,369, filed onApr. 22, 2009, titled “DEVICES AND METHODS FOR TISSUE MODIFICATION,” nowU.S. Pat. No. 8,221,397; which is a continuation of U.S. patentapplication Ser. No. 11/251,165, filed on Oct. 15, 2005, titled “DEVICESAND METHODS FOR TISSUE MODIFICATION,” now U.S. Pat. No. 7,555,307; whichclaims the benefit of U.S. Provisional Application No. 60/619,306, filedon Oct. 15, 2004, titled “METHODS AND APPARATUS FOR THE TREATMENT OFTISSUE IMPINGEMENT IN THE SPINE;” and U.S. Provisional PatentApplication No. 60/622,865, filed on Oct. 28, 2004, titled “METHODS ANDAPPARATUS FOR SELECTIVE SURGICAL REMOVAL OF TISSUE.”

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 11/405,859,filed on Apr. 17, 2006, titled “TISSUE MODIFICATION BARRIER DEVICES ANDMETHODS,” now Publication No. US-2007-0213734-A1, now abandoned; whichis a continuation-in-part of U.S. patent application Ser. No.11/375,265, filed on Mar. 13, 2006, titled “METHODS AND APPARATUS FORTISSUE MODIFICATION,” now U.S. Pat. No. 7,887,538; which is acontinuation-in-part of PCT Patent Application No. PCT/US2005/037136,filed on Oct. 15, 2005, titled “DEVICES AND METHODS FOR TISSUE REMOVAL,”now Publication No. WO2006/044727; which claims the benefit of U.S.Provisional Patent Application Nos. 60/619,306, filed on Oct. 15, 2004,titled “METHODS AND APPARATUS FOR THE TREATMENT OF TISSUE IMPINGEMENT INTHE SPINE;” 60/622,865, filed on Oct. 28, 2004, titled “METHODS ANDAPPARATUS FOR SELECTIVE SURGICAL REMOVAL OF TISSUE;” 60/681,719, filedon May 16, 2005, titled “METHODS AND APPARATUS FOR SELECTIVE SURGICALREMOVAL OF TISSUE;” 60/681,864, filed on May 16, 2005, titled “METHODSAND APPARATUS FOR SELECTIVE SURGICAL REMOVAL OF TISSUE;” and 60/685,190,filed on May 27, 2005, titled “METHODS AND APPARATUS FOR SELECTIVESURGICAL REMOVAL OF TISSUE.”

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 11/538,345,filed on Oct. 3, 2006, titled “ARTICULATING TISSUE CUTTING DEVICE,” nowPublication No. US-2008-0161809-A1, now abandoned.

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 11/870,370,filed on Oct. 10, 2007, titled “PERCUTANEOUS SPINAL STENOSIS TREATMENT,”now Publication No. US-2008-0103504-A1, now abandoned; which claims thebenefit of U.S. Provisional Patent Application No. 60/863,544, filed onOct. 30, 2006, titled “PERCUTANEOUS SPINAL STENOSIS TREATMENT.”

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 12/140,201,filed on Jun. 16, 2008, titled “DEVICES AND METHODS FOR MEASURING THESPACE AROUND A NERVE ROOT,” now Publication No. US-2008-0312660-A1, nowabandoned; which claims the benefit of U.S. Provisional PatentApplication No. 60/944,398, filed on Jun. 15, 2007, titled “NEURALFORAMEN MEASUREMENT DEVICES.”

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 12/170,392,filed on Jul. 9, 2008, titled “SPINAL ACCESS SYSTEM AND METHOD,” nowPublication No. US-2009-0018507-A1, now abandoned; which claims thebenefit of U.S. Provisional Patent Applications No. 60/948,664, filed onJul. 9, 2007, titled “SPINAL ACCESS SYSTEM AND METHOD;” and 61/048,448,filed on Apr. 28, 2008, titled “EPIDURAL ACCESS TOOLS AND METHODS.”

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 12/352,385,filed on Jan. 12, 2009, titled “DEVICES, METHODS AND SYSTEMS FOR NEURALLOCALIZATION,” now Publication No. US-2009-0171381-A1; which claims thebenefit of U.S. Provisional Patent Application No. 61/020,670, filed onJan. 11, 2008, titled “DEVICES AND METHODS FOR TISSUE LOCALIZATION ANDIDENTIFICATION.” U.S. patent application Ser. No. 12/352,385 is also acontinuation-in-part of U.S. patent application Ser. No. 12/060,229,filed on Mar. 31, 2008, titled “METHOD, SYSTEM, AND APPARATUS FOR NEURALLOCALIZATION,” now U.S. Pat. No. 7,959,577; which claims the benefit ofU.S. Provisional Patent Application No. 61/017,512, filed on Dec. 28,2007, titled “METHOD, SYSTEM, AND APPARATUS FOR TISSUE LOCALIZATION ANDIDENTIFICATION.”

U.S. patent application Ser. No. 12/816,729 is also acontinuation-in-part of U.S. patent application Ser. No. 12/496,094,filed on Jul. 1, 2009, titled “ACCESS AND TISSUE MODIFICATION SYSTEMSAND METHODS,” now Publication No. US-2010-0004654-A1; which claims thebenefit of U.S. Provisional Application No. 61/077,441, filed on Jul. 1,2008, titled “INNER SPINOUS DISTRACTION ACCESS AND DECOMPRESSIONSYSTEM.”

This patent application may also be related to U.S. patent applicationSer. No. 11/250,332, filed on Oct. 15, 2005, titled “DEVICES AND METHODSFOR SELECTIVE SURGICAL REMOVAL OF TISSUE,” now U.S. Pat. No. 7,738,968;U.S. patent application Ser. No. 11/251,205, filed on Oct. 15, 2005,titled “DEVICES AND METHODS FOR TISSUE ACCESS,” now U.S. Pat. No.7,918,849; U.S. patent application Ser. No. 11/405,848, filed on Apr.17, 2006, titled “MECHANICAL TISSUE MODIFICATION DEVICES AND METHODS,”now Publication No. US-2012-0078253-A9; U.S. patent application Ser. No.11/687,548, filed on Mar. 16, 2007, titled “TISSUE REMOVAL WITH AT LEASTPARTIALLY FLEXIBLE DEVICES,” now U.S. Pat. No. 8,062,300; and U.S.patent application Ser. No. 11/429,377, filed on May 4, 2006, titled“FLEXIBLE TISSUE RASP,” now U.S. Pat. No. 8,048,080.

INCORPORATION BY REFERENCE

All publications and patent applications mentioned in this specificationare herein incorporated by reference to the same extent as if eachindividual publication or patent application was specifically andindividually indicated to be incorporated by reference.

BACKGROUND

Minimally invasive surgical techniques typically include accessing thetissue through a small opening or port into the body. Minimally invasiveprocedures may include laparoscopic devices and remote-controlmanipulation of instruments with indirect observation of the surgicalfield through an endoscope or similar device, and may be carried outthrough the skin or through a body cavity or anatomical opening. Thismay result in shorter hospital stays, or allow outpatient treatment.

Unfortunately, the use of minimally-invasive techniques has oftenrequired a loss in control of the treatment device or implant, as thetreatment sites are often deep within the body, proving both difficultto access, as well as difficult to manipulate the device when the bodyregion is minimally invasively accessed. In particular, finding leverageto position or manipulate minimally invasive devices once deployed hasproven extremely difficult. For example, most procedures are performedfrom a single (minimally invasive) opening through the body to accessthe treatment site. Thus, any devices or implants delivered through thisopening must be controlled externally through the single opening. As aresult, complex and expensive tools have been created to allowmanipulation of distally-positioned devices or implants within the body.

Even in variations of minimally invasive procedures in which a secondaccess port is used, coordination of the two access ports at the targethas proven difficult, particularly when one or more devices are insertedthrough different access ports and required to meet at an internal site.Such minimally invasive techniques often require the additional use ofvisualization devices to guide and/or confirm device position andoperation.

Finally, manipulation of implants and devices using any of theseminimally invasive techniques has also proven difficult. For example,when treating small or enclosed body regions such as joints, or regionssurrounded by sensitive non-target tissue, manipulation of a device orimplant within this space has been limited by the ability to control thedistal end of the device from a proximal position. When a single accesspoint is used, the device or implant must generally be ‘pushed’ intoposition within or along an access device. An elongate member (e.g., acannula or guide) may be used, and the control of an implant or otherdevice depends on the configuration of the access elongate member. Thus,the application of force by the implant or treatment device may dependon the application of force from the proximal end, at some distance fromthe distal end where the implant or treatment device is located. Thismay lead to undesirable and dangerous kinking, bending, and torqueing ofthe access device and/or implant.

Described herein are methods, devices and systems for treating tissue byfirst placing a guidewire (or “pullwire”) in position within the body,and then using the guidewire to position, anchor and/or treat thetissue. In general, these methods and systems are “bimanual” procedures,in which the implant or tissue modification device is controlled withinthe body from two separate locations outside of the body. The devices,methods and systems described herein may allow precise control andanchoring of one or more devices, and therefore precise treatment oftissue, and may address many of the issues raised above. Although themethods described herein may be particularly suitable for minimallyinvasive (e.g., percutaneous) treatment of tissue, they may also be usedfor open or semi-open treatments.

In one subsection of this document, described herein are devices,methods and systems that relate generally to medical/surgical devicesand methods. More specifically, they may relate to guidewire systems andmethods for advancing one or more surgical devices between tissues in apatient.

In recent years, less invasive (or “minimally invasive”) surgicaltechniques have become increasingly more popular, as physicians,patients and medical device innovators have sought to achieve similar orimproved outcomes, relative to conventional surgery, while reducing thetrauma, recovery time and side effects typically associated withconventional surgery. Developing less invasive surgical methods anddevices, however, can pose many challenges. For example, some challengesof less invasive techniques include working in a smaller operatingfield, working with smaller devices, and trying to operate with reducedor even no direct visualization of the structure (or structures) beingtreated. These challenges are compounded by the fact that target tissuesto be modified often reside very close to one or more vital, non-targettissues, which the surgeon hopes not to damage. One of the initialobstacles in any given minimally invasive procedure, therefore, ispositioning a minimally invasive surgical device in a desired locationwithin the patient to perform the procedure on one or more targettissues, while avoiding damage to nearby non-target tissues.

Examples of less invasive surgical procedures include laparoscopicprocedures, arthroscopic procedures, and minimally invasive approachesto spinal surgery, such as a number of less invasive intervertebral discremoval, repair and replacement techniques.

One area of spinal surgery in which a number of less invasive techniqueshave been developed is the treatment of spinal stenosis. Spinal stenosisoccurs when neural and/or neurovascular tissue in the spine becomesimpinged by one or more structures pressing against them, causing one ormore symptoms. This impingement of tissue may occur in one or more ofseveral different areas in the spine, such as in the central spinalcanal, or more commonly in the lateral recesses of the spinal canaland/or one or more intervertebral foramina.

FIGS. 352-354 show various partial views of the lower (lumbar) region ofthe spine. FIG. 352 shows an approximate top view of a vertebra with thecauda equina (the bundle of nerves that extends from the base of thespinal cord through the central spinal canal) shown in cross section andtwo nerve roots exiting the central spinal canal and extending throughintervertebral foramina on either side of the vertebra. The spinal cordand cauda equina run vertically along the spine through the centralspinal canal, while nerve roots branch off of the spinal cord and caudaequina between adjacent vertebrae and extend through the intervertebralforamina. Intervertebral foramina may also be seen in FIGS. 353 and 354,and nerves extending through the foramina may be seen in FIG. 353.

One common cause of spinal stenosis is buckling and thickening of theligamentum flavum (one of the ligaments attached to and connecting thevertebrae), as shown in FIG. 352. (Normal ligamentum flavum is shown incross section in FIG. 354) Buckling or thickening of the ligamentumflavum may impinge on one or more neurovascular structures, dorsal rootganglia, nerve roots and/or the spinal cord itself. Another common causeof neural and neurovascular impingement in the spine is hypertrophy ofone or more facet joints (or “zygopophaseal joints”), which providearticulation between adjacent vertebrae. (Two vertebral facet superiorarticular processes are shown in FIG. 352. Each superior articularprocess articulates with an inferior articular process of an adjacentvertebra to form a zygopophaseal joint. Such a joint is labeled in FIG.354.) Other causes of spinal stenosis include formation of osteophytes(or “bone spurs”) on vertebrae, spondylolisthesis (sliding of onevertebra relative to an adjacent vertebra), facet joint synovial cysts,and collapse, bulging or herniation of an intervertebral disc into thecentral spinal canal. Disc, bone, ligament or other tissue may impingeon the spinal cord, the cauda equina, branching spinal nerve rootsand/or blood vessels in the spine to cause loss of function, ischemiaand even permanent damage of neural or neurovascular tissue. In apatient, this may manifest as pain, impaired sensation and/or loss ofstrength or mobility.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% of adults aged 50 and older and is the most frequentreason cited for back surgery in patients aged 60 and older.Conservative approaches to the treatment of symptoms of spinal stenosisinclude systemic medications and physical therapy. Epidural steroidinjections may also be utilized, but they do not provide long lastingbenefits. When these approaches are inadequate, current treatment forspinal stenosis is generally limited to invasive surgical procedures toremove ligament, cartilage, bone spurs, synovial cysts, cartilage, andbone to provide increased room for neural and neurovascular tissue. Thestandard surgical procedure for spinal stenosis treatment includeslaminectomy (complete removal of the lamina (see FIGS. 352 and 353) ofone or more vertebrae) or laminotomy (partial removal of the lamina),followed by removal (or “resection”) of the ligamentum flavum. Inaddition, the surgery often includes partial or occasionally completefacetectomy (removal of all or part of one or more facet joints). Incases where a bulging intervertebral disc contributes to neuralimpingement, disc material may be removed surgically in a discectomyprocedure.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the affected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. In a spinal fusion procedure, the vertebrae are attached togetherwith some kind of support mechanism to prevent them from moving relativeto one another and to allow adjacent vertebral bones to fuse together.Unfortunately, a surgical spine fusion results in a loss of ability tomove the fused section of the back, diminishing the patient's range ofmotion and causing stress on the discs and facet joints of adjacentvertebral segments. Such stress on adjacent vertebrae often leads tofurther dysfunction of the spine, back pain, lower leg weakness or pain,and/or other symptoms. Furthermore, using current surgical techniques,gaining sufficient access to the spine to perform a laminectomy,facetectomy and spinal fusion requires dissecting through a wideincision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Discectomy procedures require entering through an incision in thepatient's abdomen and navigating through the abdominal anatomy to arriveat the spine. Thus, while laminectomy, facetectomy, discectomy, andspinal fusion frequently improve symptoms of neural and neurovascularimpingement in the short term, these procedures are highly invasive,diminish spinal function, drastically disrupt normal anatomy, andincrease long-term morbidity above levels seen in untreated patients.Although a number of less invasive techniques and devices for spinalstenosis surgery have been developed, these techniques still typicallyrequire removal of significant amounts of vertebral bone and, thus,typically require spinal fusion.

Therefore, it would be desirable to have less invasive surgical methodsand systems for treating spinal stenosis. For example, it would bedesirable to have devices or systems for positioning a less invasivedevice in a patient for performing a less invasive procedure. Ideally,such systems and devices would be less invasive than currently availabletechniques and thus prevent damage to non-target vertebral bone andneural and neurovascular structures. Also ideally, such systems anddevices would also be usable (or adaptable for use) in positioning asurgical device in parts of the body other than the spine, such as injoints for performing various arthroscopic surgical procedures, betweena cancerous tumor and adjacent tissues for performing a tumor resection,and the like.

In particular, it would be useful to provided devices, systems andmethods for gaining access using a guidewire that could be easilyexchanged to position and apply tension to a plurality of devices,including surgical devices such as tissue localization devices, tissuemodification devices, or the like. Described herein are devices, methodsand system which may address these needs.

SUMMARY OF THE DISCLOSURE

In various embodiments, devices, systems and methods of the presentinvention provide minimally invasive or less invasive modification oftissue in a patient. For the purposes of this application, the phrase“tissue modification” includes any type of tissue modification, such asbut not limited to removing, cutting, shaving, abrading, shrinking,ablating, shredding, sanding, filing, contouring, carving, melting,heating, cooling, desiccating, expanding, moving, delivering medicationor other substance(s) to tissue and/or delivering an implantable device(such as a stent) to tissue.

In one aspect of the present invention, a device for modifying tissue ina patient may include: an elongate body having a rigid proximal portionand a flexible distal portion having first and second major surfaces; aproximal handle coupled with the proximal portion of the body; one ormore tissue modifying members disposed along the first major surface ofthe distal portion of the body; a guidewire coupled with and extendingfrom the distal portion of the body; and a distal handle removablycoupleable with the guidewire outside the patient. In some embodiments,the device may be configured to modify spinal tissue, and the device maybe configured to extend into the patient's body, along a curved paththrough an intervertebral foramen of the spine, and out of the patient'sbody, such that at least part of the flexible distal portion of theelongate body of the device extends into the intervertebral foramen, andthe proximal and distal handles reside outside the patient. In oneembodiment, a height of the tissue modifying member(s) may be greaterthan a thickness of a ligamentum flavum of the spine. In alternativeembodiments, the device may be configured for use in modifying any of anumber of other tissues in the spine or in other parts of a patient'sbody. In one embodiment, for example, a device may be used to incise thetransverse carpal ligament while inhibiting damage of the median nerveto perform a minimally invasive carpal tunnel release procedure. Othertissues in the knee, shoulder, elbow, foot, ankle or other parts of thebody may be addressed in alternative embodiments.

In various alternative embodiments, the tissue modifying member(s) of atissue modification device may include, but are not limited to, one ormore uni-directional blades, bi-directional blades, teeth, hooks, barbs,hooks, pieces of Gigli saw (or other wire saw), wires, meshes, wovenmaterial, knitted material, braided material, planes, graters, raisedbumps, other abrasive surfaces, other abrasive materials and/ordeliverable substances adhered to or formed in the first major surface.Some embodiments may include one type of tissue modifying member, whileother embodiments may include a combination of different tissuemodifying members. In some embodiments, the tissue modifying member(s)may be fixedly attached to or formed in the first major surface, and thedevice may operate by reciprocating the entire device (or most of it)back and forth to cause the tissue modifying member(s) to modify tissue.In alternative embodiments, the tissue modifying member(s) may bemoveably attached to or formed in the first major surface, and thedevice may further include an actuator coupled with the tissue modifyingmember(s) and extending to the proximal handle for actuating the tissuemodifying member(s).

In one embodiment, the elongate body may be at least partially hollow,the distal portion may be flatter than the proximal portion, and thetissue modifying members may comprise blades formed in the first majorsurface of the distal portion. In some embodiments, the guidewire may beremovably coupled with the distal portion of the elongate body via aguidewire coupler comprising a cavity for containing a shaped tip of theguidewire, and wherein the guidewire comprises at least one shaped tipfor fitting within the cavity.

Some embodiments may further include a material disposed over a portionof the elongate body distal portion to provide the distal portion withsmooth edges. For example, such a material may comprise, in someembodiments, a polymeric cover disposed over the distal portion with oneor more openings through which the tissue modifying member(s) protrude.In one embodiment, the material may be further configured to collecttissue removed by the tissue modifying member(s). In some embodiments,the device may include a tissue collection chamber formed in or attachedto the elongate body.

In another aspect of the present invention, a device for modifyingtissue in a patient may include an elongate body, a proximal handlecoupled with the proximal portion of the body, one or more tissuemodifying members disposed along the first major surface of theintermediate portion of the body, and a distal handle removablycoupleable with the distal portion of the body outside the patient. Insome embodiments, the elongate body may include a rigid proximalportion, a flexible distal portion, and an intermediate flexible portiondisposed between the proximal and distal portions and having first andsecond major surfaces. In some embodiments, the device may be configuredto modify spinal tissue, and the device may be configured to extend intothe patient's body, along a curved path through an intervertebralforamen of the spine, and out of the patient's body, such that at leastpart of the flexible intermediate portion of the elongate body of thedevice extends into the intervertebral foramen, and the proximal anddistal handles reside outside the patient.

In some embodiments, the distal portion of the elongate body maycomprise a guidewire coupled with the intermediate portion of the body.In some embodiments, at least the proximal and intermediate portions ofthe elongate body are at least partially hollow, thus forming at leastone lumen. For example, in some embodiments, the at least one lumen mayinclude a suction lumen and/or an irrigation lumen. Optionally, someembodiments may include at least one tissue transport member slideablydisposed within the lumen and configured to remove tissue out of thedevice. For example, in one embodiment the tissue transport member maycomprise one or more flexible wires having tissue collection portionsdisposed under the tissue modifying member(s) of the device. Such tissuecollection portions may include, for example, shaped portions of thewire(s), adhesive coating(s) on the wire(s), tissue collectingmaterial(s) on the wire(s), adhesive material(s) used to make thewire(s) themselves and/or the like. In alternative embodiments, thetissue transport member may comprise a piece of tissue adhering materialdisposed under the tissue modifying member(s) of the device. In otheralternative embodiments, the tissue transport member may comprise aremovable tissue collection chamber disposed under the tissue modifyingmember(s) of the device. Alternatively, the tissue transport member maycomprise at least one unidirectional valve for allowing tissue to passthrough the shaft toward the proximal handle while preventing the cuttissue from passing through the valve(s) toward the tissue modifyingmember(s) of the device.

In some embodiments, at least part of the elongate body may besufficiently flexible to be compressible, such that tissue may be movedthrough the elongate body by compressing the compressible portion. Someembodiments of the device may further include a tissue collectionchamber formed in or attached to the elongate body.

In another aspect of the present invention, a kit for modifying tissuein a patient may include a tissue modification device, a guidewireconfigured to couple with a guidewire coupler of the device, and adistal handle removably coupleable with the guidewire outside thepatient. The tissue modification device may include a rigid shaft havinga proximal end and a distal end, a flexible substrate extending from thedistal end of the shaft, a proximal handle coupled with the shaft at ornear its proximal end, one or more tissue modifying members disposedalong one side of the substrate, and a guidewire coupler disposed on thesubstrate. In some embodiments, the tissue modification device andguidewire, coupled together, may be configured to extend into thepatient's body, along a curved path through an intervertebral foramen ofthe spine, and out of the patient's body, such that at least part of theflexible substrate extends into the intervertebral foramen, and theproximal and distal handles reside outside the patient.

Optionally, some embodiments may also include at least one probe forpassing the guidewire between target and non-target tissues in apatient. For example, in some embodiments, the probe may comprise aneedle. In alternative embodiments, the probe may comprise a curved,cannulated probe. In any case, a probe may optionally include a flexibleguide member for passing through the probe, and such a guide member mayhave an inner diameter selected to allow passage of the guidewiretherethrough.

In some embodiments, the tissue modification device may further includea tissue collection member coupled with the substrate and configured tocollect tissue. Such an embodiment may optionally further include tissuetransport means configured to transport the collected tissue through thedevice.

In another aspect of the present invention, a method for modifyingtarget tissue in a patient while inhibiting damage to non-target tissuesmay involve: advancing a flexible distal portion of an elongate tissuemodification device into the patient's body and along a curved pathbetween target and non-target tissues, such that a distal end of thedistal portion exits the patient's body; coupling a first handle withthe distal portion outside the patient; applying a first tensioningforce to the first handle; applying a second tensioning force to asecond handle coupled with a rigid proximal portion of the device, thefirst and second tensioning forces urging one or more tissue modifyingmembers disposed along the flexible distal portion against the targettissue; and reciprocating at least a portion of the device back andforth, while maintaining at least some of the tensioning force, to causethe tissue modifying member(s) to modify the target tissue.

In some embodiments, advancing the distal portion may involve advancingthrough an intervertebral foramen of the patient's spine, andreciprocating the device may involve modifying ligamentum flavum and/orbone. In some embodiments, advancing the distal portion may involveadvancing percutaneously into the patient. In some embodiments, thedistal portion of the device may be advanced into the patient's spinewithout removing bone, and only ligamentum flavum tissue may bemodified. The method may optionally further involve manipulating thesecond handle and thus the rigid proximal portion to steer the flexibleportion of the device.

In one embodiment, the flexible distal portion may include a flexiblesubstrate coupled with a flexible guidewire, coupling the first handlemay involve coupling with the guidewire, and advancing the distalportion may involve pulling the guidewire with the first handle toadvance the flexible substrate between the target and non-target tissue.In various embodiments, the target tissue may include, but is notlimited to, ligament, tendon, bone, tumor, cyst, cartilage, scar,osteophyte and inflammatory tissue, and the non-target tissue mayinclude, but is not limited to, neural tissue and neurovascular tissue.In one embodiment, for example, the target tissue may include atransverse carpal ligament, and the non-target tissue may include amedian nerve.

In some embodiments, the tensioning forces may urge a plurality oftissue modifying members against a curved target tissue along a lengthof the flexible portion. In some embodiments, reciprocating at least aportion of the device may involve reciprocating an entire portionbetween the first and second handles, and reciprocating may cause atissue modifying surface of the flexible portion to modify the targettissue while an atraumatic surface of the flexible portion faces thenon-target tissue. In alternative embodiments, reciprocating at least aportion of the device may involve reciprocating a tissue modifyingsurface of the flexible portion, and reciprocating may cause the tissuemodifying surface to modify the target tissue while an atraumaticsurface of the flexible portion faces the non-target tissue.

Optionally, in some embodiments, the method may further involvecollecting cut tissue in the tissue modification device. In someembodiments, the method may additionally include transporting the cuttissue out of the patient through the tissue modification device. Forexample, transporting the cut tissue may involve applying suction and/orirrigation in the tissue collection chamber. Alternatively, transportingthe cut tissue may involve collecting the cut tissue on or in one ormore tissue transport members and withdrawing the tissue transportmember(s) through the tissue modification device.

In another aspect, the invention provides a method for removing a targetligament and/or bone tissue of a patient. The method comprises providingan elongate body having an axis and an elongate, axially flexibleportion affixed to a rigid shaft portion. The flexible portion ispositioned within the patient so that a first surface of the flexibleportion is oriented toward the target tissue. The first surface isshifted toward a target region of the target tissue by moving the rigidportion, and the target region of the target tissue is removed with atissue modifying member disposed along the first surface.

Optionally the rigid portion extends axially from a first end of theflexible portion. The flexible portion can be flexible in one lateralorientation, and may be stiffer in another lateral orientation (forexample, in the direction in which it is shifted). The flexible portioncan be positioned so that the first surface of the flexible portionbends over the target tissue, and/or the flexible portion may be axiallytensioned to urge the first surface toward the target tissue. Thetension can be applied to the first end by pulling the rigid portionfrom outside the patient.

In many embodiments, the surface will be shifted by applying torque tothe rigid portion from outside the body portion. The rigid portion canthen rotate the flexible portion about the axis so as to shift anorientation of the first surface toward a target region of the targettissue. Where the target tissue has a convex surface defining an outwardorientation and an inward orientation, and where the first surface isbordered by first and second opposed edges, the target tissue adjacentthe first edge may be inward of the target tissue adjacent the secondedge. As a result, the tension of the flexible portion may inducerolling of the flexible portion about the axis toward the first edge.The torquing of the shaft portion may counteract the tension-inducedrolling to inhibit flipping of the flexible portion.

A distal handle may be coupled with a second end of the flexibleportion, and the flexible portion may be manually tensioned bysimultaneous pulling, from outside the patient, on the first and secondhandles. Axially moving the tissue modifying member along a curving pathmay be performed within the patient by relative movement between thefirst and second handles, the curving path including the bend over thetarget tissue. Lateral translation of the rigid portion from outside thepatient can be used to induce the lateral shifting of the first surface,particularly where the flexible portion is stiffer in a second lateralorientation extending along the first surface, with the first surfacetypically shifting along that second lateral orientation.

In some embodiments, pivoting of the rigid portion about tissuesdisposed along the rigid portion may be used to induce the lateralshifting of the first surface. Optionally, a first handle may beattached to the rigid portion outside the patient, and the flexibleportion can be manually tensioned and shifted by manipulating the firsthandle with a hand. A distal handle can be coupled with a second end ofthe flexible portion, and the flexible portion can be manually tensionedby simultaneous pulling, from outside the patient, on the first andsecond handles. Axially moving of the tissue modifying member along acurving path within the patient can be effected by relative movementbetween the first and second handles, typically with the curving pathincluding a bend over the target tissue. Reciprocation of the tissuemodifying member along the curved path and against the target tissue canbe provided by sequentially pulling on the first and second handles sothat a cutting edge of the tissue modifying member incises the targettissue. In some embodiments, another rigid portion extends from thesecond handle to the second end of the flexible portion inside thepatient, with the first surface of the flexible portion being shiftedusing both rigid portions.

In yet another aspect, the invention provides a system for removing atarget tissue of a patient. The system comprises an elongate flexibleportion having a first end and a second end with an axis therebetween.The flexible portion has a first surface extending along the axis and isaxially bendable in a first lateral orientation. A rigid portion isextendable from the flexible body portion so that pulling on the rigidportion can axially tension the flexible portion to urge the firstsurface toward the target tissue. Movement of the rigid portion can beused to shift the first surface toward a target region of the targettissue. A tissue modifying member disposed along the first surface canbe configured to effect removal of the target region of the targettissue.

In one aspect of the present invention, a device for removing tissuefrom a patient may include: an elongate flexible body having a proximalend, a distal end, and a longitudinal axis therebetween, the elongatebody having opposed first and second major surfaces with a lateralorientation across the axis; and a plurality of blades distributedlaterally across the first major surface. Each blade may have a firstend adjacent the first surface and extending to a cantilevered secondend, a first edge between the first and second ends of the blade beingoriented toward the distal end of the elongate body, a second edgebetween the first and second ends of the blade being oriented toward theproximal end of the elongate body, a height of the blade between itsfirst and second ends, and an axial length of the blade between itsfirst and second edges. The first edge and/or the second edge maycomprise a cutting edge so as to axially cut the ligament when the firstsurface is urged toward the ligament and the elongate body advancesalong a path toward one end of the elongate body. Both the height andthe axial length of each blade may be greater than a transverse width ofthe blade.

In some embodiments, each blade of the device may have an associatedbase extending along and affixed to the first surface with an angle orbend therebetween. Additionally, in some embodiments, at least some ofthe bases may be disposed laterally between a first associated blade anda second associated blade. In some embodiments, both the first edge andthe second edge of each blade may comprise a cutting edge so as toaxially cut the ligament and effect removal of the ligament when theelongate body reciprocates along the path.

In one embodiment, the tissue may comprise ligament tissue disposed overa curved bone surface, the second ends of at least some of the bladesmay comprise bone-cutting tips and extend to a distal bone-engagementheight from the first surface, and tension forces applyable manually tothe proximal and distal ends of the elongate body may urge the bonecutting tips through the ligament and into the bone when the firstsurface bends over the ligament tissue and the elongate body isreciprocated axially. In some embodiments, the first surface, whenbending over the bone surface, may have an active region with bladesthat can be urged into the ligament, and the manual tension forcesdivided by a combined surface area of the bone cutting tips within theactive region may be at least about 30,000 psi.

In an alternative embodiment, the tissue may comprise ligament tissuedisposed over a curved bone surface, the second ends of at least some ofthe blades may comprise bone-protecting surfaces and extend to a boneprotecting height from the first surface, and tension forces applyablemanually to the proximal and distal ends of the elongate body may resultin sliding of the bone-protecting surfaces along the bone surface so asto inhibit removal of the bone when the first surface bends over theligament tissue and the elongate body is reciprocated axially.

In another alternative embodiment, the tissue may comprise ligamenttissue disposed over a curved bone surface, the second ends of at leastsome of the blades may comprise bone-contacting edges and extend to abone-contacting height from the first surface, a first amount of tensionforce applyable manually to the proximal and distal ends of the elongatebody may result in sliding of the bone-contacting edges along the bonesurface so as to inhibit removal of the bone when the first surfacebends over the ligament tissue and the elongate body is reciprocatedaxially, and a second amount of tension force applyable manually to theproximal and distal ends of the elongate body may cause thebone-contacting edges to cut bone when the first surface bends over theligament tissue and the elongate body is reciprocated axially.

In some embodiments, a frontal surface area of the first or second edgeof each blade may be less than a side surface area of each blade. Insome embodiments, a side of each blade between its two edges may form anangle with the first surface of the elongate body of between about 45degrees and about 90 degrees, and the side of each blade may be alignedat an angle of between about 0 degrees and about 45 degrees relative tothe longitudinal axis of the elongate body. Even more preferably, insome embodiments, the side of each blade may form an angle with thefirst surface of between about 60 degrees and about 90 degrees, and theside of each blade may be aligned at an angle of between about 0 degreesand about 30 degrees relative to the longitudinal axis of the elongatebody. In some embodiments, at least two blades may be aligned atdifferent angles relative to the longitudinal axis of the elongate body.

In some embodiments, the elongate body may be configured to bend over acurved surface. In some embodiments, at least some of the blades may beaxially offset from one another along the longitudinal axis of theelongate body.

In some embodiments, the device may be configured to modify spinaltissue, and the elongate body may be configured to extend into thepatient's body, along a curved path through an intervertebral foramen ofthe spine, and out of the patient's body, such that a flexible portionof the elongate body of the device extends through the intervertebralforamen. In some embodiments, a height of each blade may be at leastequal to a thickness of a ligamentum flavum of the spine.

In some embodiments, the elongate body may include a rigid shaft, aflexible portion extending from one end of the shaft, a guidewirecoupler on or in the flexible portion, and a first handle coupled withan end of the shaft opposite the flexible portion. Optionally, thedevice may further include a guidewire configured to couple with theguidewire coupler and a second handle configured to couple with theguidewire outside the patient.

In various alternative embodiments, the second end of each blade mayhave a shape such as but not limited to a pointed tip, a flat edge, around edge, a serrated edge, a saw-toothed edge or a curved edge. Insome embodiments, second ends of at least two blades may have differentshapes, relative to one another. In some embodiments, at least twoblades may have different heights, relative to one another. In someembodiments, the blades may be fixedly attached to the first majorsurface.

In another aspect of the present invention, a device for removing tissuefrom a patient may include an elongate flexible body having a proximalend, a distal end, and a longitudinal axis therebetween, the elongatebody having opposed first and second major surfaces with a lateralorientation across the axis and a plurality of blades distributedlaterally across the first major surface, each blade having a first endadjacent the first surface and extending to a cantilevered second end.Each blade may substantially in-line with the longitudinal axis of theelongate body. Additionally, each blade may be substantially verticalrelative to the first surface. By “substantially in-line,” it is meantthat a side of each blade is aligned at an angle of between about 0degrees and about 45 degrees relative to the longitudinal axis of theelongate body. By “substantially vertical,” it is meant that each bladeforms an angle with the first surface of the elongate body of betweenabout 45 degrees and about 90 degrees. In some preferred embodiments,the side of each blade may be aligned at an angle of between about 0degrees and about 30 degrees relative to the longitudinal axis of theelongate body, and the side of each blade may form an angle with thefirst surface of between about 60 degrees and about 90 degrees.

In another aspect of the present invention, a method for removing targettissue from a patient may involve advancing an elongate flexible bodyalong a path between the target tissue and a non-target tissue, theflexible body having a plurality of laterally offset, cantileveredblades extending therefrom, and advancing the blades through the targettissue by moving the elongate body axially along the path so as to formlaterally offset cuts in the target tissue. In some embodiments, thetarget tissue may comprise ligament tissue disposed over bone, advancingthe elongate body may involve advancing along a curved path, and themethod may further involve applying pulling force at or near oppositeends of the elongate body to urge the laterally offset blades into theligament tissue, such that at least one of the blades contacts the bonebeneath the ligament.

In some embodiments, advancing the blades involves reciprocating theelongate body along the curved path. Some embodiments may furtherinvolve reciprocating the elongate body to remove a portion of the bone.In some embodiments, the elongate body may be advanced into anintervertebral foramen of the patient's spine, the target ligamenttissue may comprise ligamentum flavum, and the non-target tissue maycomprise neural tissue. Optionally, such a method may further includesteering the elongate body sideways within the intervertebral foramenduring the advancing step. In some embodiments, at least some of theblades may be angled relative to the longitudinal axis of the elongatebody, and advancing the blades through the target tissue may causecantilevered ends of the blades to ride along the bone to cause theelongate body to move sideways within the intervertebral foramen.

In some embodiments, the elongate body may be advanced percutaneouslyinto the patient by pulling the device behind a guidewire. Someembodiments may further involve inhibiting damage to the non-targettissue with an atruamatic surface of the elongate body configured tocontact the non-target tissue when the blades contact target tissue.Some embodiments of the method may further involve collecting cut tissuebetween at least some of the blades.

In another aspect of the present invention, a method for removingligamentum flavum tissue in a spine of a patient to treat spinalstenosis may involve: advancing a flexible elongate body of a tissuemodification device along a curved path through an intervertebralforamen in the spine, between ligamentum flavum and neural tissue;applying pulling force at or near opposite ends of the elongate body toadvance at least one cantilevered, laterally offset blade coupled with afirst major surface of the elongate body through the ligamentum flavumto contact vertebral bone, wherein each blade is substantially in-linewith a longitudinal axis of the elongate body, and wherein each blade issubstantially vertical relative to a the first major surface; andreciprocating the elongate body to remove ligamentum flavum tissue,wherein reciprocating the device while applying the force causes atleast one of the blades to ride along the bone and move the elongatebody laterally in the intervertebral foramen, relative to thelongitudinal axis of the elongate body. In some embodiments, the methodmay further involve inhibiting damage to the neural tissue with anatraumatic second major surface of the elongate body opposite the firstmajor surface.

Also described herein are devices for modifying tissue in a patient thatinclude: an elongate body having a proximal end and a distal end(wherein the elongate body comprises opposing first and second majorsurfaces laterally extending between the proximal and distal ends); atissue collection region between the first and second surfaces; and oneor more tissue modifying members disposed along the first major surfaceand configured to cut the tissue when the tissue modifying members areurged against the tissue.

The first and second major surfaces may be flexible. In some variations,the proximal end comprises a rigid portion and the distal regioncomprises a flexible distal portion that includes the first and secondmajor surfaces, and further comprising a proximal handle coupled withthe proximal region of the elongate body.

The first major surface may have a smaller radius of curvature than thesecond major surface.

In some variations, the device further includes one or more valveswithin the tissue collection region configured to limit the passage ofcut tissue towards the tissue modifying members (e.g., one-way valves).In other variations, the device includes a floating substrate configuredto limit the tissue modifying member based on the amount of material inthe tissue collection region.

In some variations, the device includes a tissue transporter that isoperably connected with the tissue collection region and configured toremove tissue from the tissue collection region adjacent the tissuemodification member. For example, the tissue transporter may comprise atleast one of: an irrigation channel and an aspiration channel. Thetissue transporter may comprise a pull wire, a belt, and/or aretractable member.

The device may also include a channel in communication with the tissuemodifying member, wherein the channel is configured to direct tissueinto the tissue collection region.

In some variations, the tissue modifying member forms a channelconfigured to direct tissue into the tissue collection region.

The tissue collection region may be expandable and/or removable.

Also described herein are devices for modifying tissue in a patient thatinclude: an elongate body having a proximal end and a distal end(wherein the elongate body comprises opposing first and second majorsurfaces laterally extending between the proximal and distal ends); oneor more tissue modifying members disposed along the first major surfaceand configured to cut the tissue when the tissue modifying members areurged against the tissue; and a channel in communication with the tissuemodifying member and a tissue collection region. The device may alsoinclude a proximal handle coupled to the proximal region of the elongatebody.

The tissue collection region may be located between the first and secondmajor surfaces.

In some variations, the device further includes a tissue transporterthat is operably connected with the tissue collection region andconfigured to remove tissue from the tissue collection region.

As mentioned, the tissue collection region may be removable and/orexpandable.

Also described herein are methods of removing tissue from a patient,including the steps of: advancing an elongate tissue modification deviceadjacent to a target tissue, driving the tissue modifying membersagainst the target tissue, cutting the target tissue with the tissuemodifying member, and collecting at least some of the cut tissue withinthe tissue collection region. The elongate tissue modification devicetypically comprises an elongate body having a proximal end and a distalend (wherein the elongate body includes opposing first and second majorsurfaces that laterally extend between the proximal and distal ends);one or more tissue modifying members disposed along the first majorsurface and configured to cut the tissue when the tissue modifyingmembers are urged against the tissue; and a tissue collection regionconfigured to collect tissue. The tissue modification member may bedriven against the target tissue by applying tension to the distal andproximal ends of the elongate body.

In some variations, the method of removing tissue also includes the stepof moving the cut tissue away from the tissue modifying members. In somevariations, the tissue may be removed by either vacuum or fluid flow.

The method may also include the step of replacing the tissue collectionregion.

Also described herein are methods of removing tissue from a subjectincluding the steps of: advancing an elongate tissue modification deviceadjacent to a target tissue; driving the tissue modifying membersagainst the target tissue; cutting the target tissue with the tissuemodifying members; collecting at least some of the cut tissue within thetissue collection region; and removing tissue from the tissue collectionregion near the tissue modifying members. The elongate tissuemodification device of this method may include an elongate body having aproximal end and a distal end (wherein the elongate body comprisesopposing first and second major surfaces that laterally extend betweenthe proximal and distal ends) one or more tissue modifying membersdisposed along the first major surface and configured to cut the tissuewhen the tissue modifying members are urged against the tissue, and atissue collection region configured to collect tissue. In somevariations, the tissue is removed by either vacuum or fluid flow.

In view of the foregoing, the present invention provides apparatus andmethods for selective removal of tissue, e.g., soft tissue and bone,preferably in a minimally invasive fashion. An embodiment of the presentinvention provides apparatus and methods for safe and selective deliveryof surgical tools into to the epidural space; and for apparatus methodsthat enable safe and selective surgical removal, ablation, andremodeling of soft tissue and bone, preferably in a minimally invasivefashion, with the apparatus delivered into the epidural space. In animportant preferred variation of the methods and apparatus are used totreat neural and neurovascular impingement in the spine, through a novelapproach to safe and selective enlargement of the pathologically narrowspinal neural foramen, the impinged lateral recess, and central canal.

In a preferred embodiment, the methods and apparatus include theplacement of a working backstop or barrier into the epidural space orneural foramina, to a location between the tool positioned for tissuealteration, and adjacent vulnerable neural or vascular structures, tohelp prevent neural or vascular injury during surgery. In a furtherpreferred embodiment, the methods and apparatus utilize neuralstimulation techniques, to enable neural localization, as a means ofimproving the safety of the procedure.

In one variation of the present invention, an epidural needle may beconverted to a working tool in order to resect or remodel spinal tissue,which is enabled by the use of herein described methods and apparatus:

After placement of an epidural needle into the epidural space, a specialepidural catheter is threaded through the needle into the epiduralspace. This catheter apparatus contains a needle tip cover in its distalend, which, after it is converted to an open position in the epiduralspace, is pulled back over the needle tip, by pulling on the proximalportion of the catheter. The catheter based cover blunts and therebyprotects the vulnerable structures of the spine, such as the dura, fromthe sharp epidural needle tip. With the epidural needle tip covered, theneedle may be more safely advanced into the epidural space, in adirection somewhat parallel to the dura, towards the contralateral oripsilateral lateral recess and neural foramen. The needle may beadvanced blindly; with image guidance; or with endoscopic guidance.

The epidural catheter, with the cap or cover for the epidural needle,may or may not contain a rigid or flexible fiberoptic cable. With afiberoptic element and a clear tip to the catheter, the epidural needlemay be converted to an epidural endoscope or “needlescope”.

One preferred embodiment of the epidural needle apparatus contains twoadjacent lumens (“double barreled”), with a working channel adjacent tothe epidural needle. The working channel may be fixed and permanent, orremovable, as in with a rail and track connection. A removable workingchannel, in one embodiment, may be inserted or removed while the tip ofthe epidural needle remains in the epidural space. The distal beveledopening of the working channel, in a preferred variation, is locatedproximal to and on the same side of the needle as the epidural needletip beveled opening faces, facilitating visualization of the workingchannel tools when a fiberoptic element has been placed in through theepidural needle lumen.

The epidural needle or the working channel of the epidural needle may bea vehicle for insertion of a working backstop or barrier, anotherapparatus that facilitates safe tissue resection and remodeling in theepidural space. The barrier is a thin flat device that may be deliveredinto or adjacent to the epidural space or neural foramina, through theneedle or working channel, or through an endoscope or open incision.Such a backstop may consist of a flexible, curved, thin and flat pieceof material. This barrier will serve to protect neural and neurovascularstructures from being damaged during tissue manipulation and resection,because it will be placed between the tissue to be ablated, resected,irritated, manipulated or remodeled, and the vulnerable neural andvascular structures or dura. The tools for tissue resection and ablationwill be used on the side of the barrier opposite from the vulnerableneural and vascular structures, which will be safely protected frominadvertent injury.

In one variation of the present invention, a tissue abrasion device isplaced, either percutaneously or through an open surgical approach,through the neural foramina of the spine, around the anterior border ofthe facet joint, and anterior to the ligamentum flavum. The abrasiondevice alternatively or additionally may be placed through the neuralforamen anterior to the facet joint, but through or posterior to theligamentum flavum. After spinal neuroforaminal placement, the device isused to remove tissues that impinge on the neurovascular structureswithin the lateral recess and neural foramen, anterior to the facetjoint.

The abrasion device may, for example, include a thin belt or ribbon,with an abrasive, shaving, and/or cutting surface, which is placedthrough the neural foramina and is held firmly against the tissue to beremoved. The belt optionally may be placed, at least partially, within aprotective sheath or covering, with the treatment area exposed to theabrasive surface of the device somewhat limited to the area where tissueabrasion and removal is desired. The abrasive element may be provided inone or more of a variety of potentially interchangeable shapes, rangingfrom flat to curved; narrow to wide; or solid to perforated. Theabrasive surface may also have various enabling designs, or surfacepatterns, or coarseness of abrasive material. The apparatus is placedwith both free ends of the abrasive element, as well as the ends of theoptional protective sleeve or covering, external to the patient formanipulation by a medical practitioner.

When the optional protective sleeve or sheath is provided, both ends ofthe sleeve may be held under tension, external to the patient, such thatthe abrasive belt or ribbon may be pulled back and forth through thesleeve without causing significant friction against and/or trauma toadjacent tissues. Initially, both ends of the abrasive ribbon are pulledsimultaneously, pulling the device in a posterior and/or lateraldirection, thereby bringing impinging spinal tissue in contact with theabrasive and/or cutting surface of the ribbon. When one end of theribbon is pulled with more force than the other, the ribbon moves in thedirection of the stronger pull, while the lesser pull on the oppositeend maintains force and creates friction with movement between theabrasive surface and the tissue to be resected.

In an open surgical variation, the ribbon or belt and/or the protectivecovering or sleeve may be placed through the surgical incision. In apercutaneous variation, the device may be inserted through a needle orover a wire. As with the percutaneous approaches, placement may be aidedby the use of image guidance and/or the use of an epidural endoscope.

Once the surgical apparatus has been placed, the medical practitionermay enlarge the lateral recess and neural foramina via cutting, shaving,filing, rasping, sanding, ablating or frictional abrasion, i.e., bysliding the abrasive or cutting surface across the tissue to beresected. Impinging tissue to be targeted for abrasion may include, butis not limited to, lateral ligamentum flavum, anterior and medial facet,and osteophytes. The medical practitioner controls the force and speedof the abrasive surface against the tissue to be removed, while optionalcovers define the tissue exposed to the abrasive element.

One variation of the abrasive element cover envelopes the abrasivesurface and the backside of the belt or ribbon in areas where tissueremoval is not intended. A nerve stimulator may be incorporated into thetissue removal surface and/or the protective cover or sleeve in order toverify correct placement and enhance safety by allowing the medicalpractitioner to ensure that neural tissue is not subject to inadvertenttrauma or abrasion during the procedure.

The present invention also describes methods and apparatus that may beused as a compression dressing, after tissue resection or ablation.Following neuroforaminal and lateral recess enlargement, one variationof the compression dressing is placed in a position where it is firmlywrapped against the abraded tissue surface around the facet andligamentum flavum through the neural foramina. By tightly pressingagainst treated tissue surfaces, such a device serves to promote desiredtissue remodeling; to prevent edema that may lead to impingement onneural or vascular tissue during early healing; to contain debris; topromote postoperative hemostasis; to block scar formation between theraw tissue surfaces and the adjacent neural and vascular structures; toavoid inflammation or irritation to neural and vascular structures fromcontact with adjacent resected tissue surfaces; and as a mechanism forsustained drug delivery, possibly as a depot, to the operative sitepost-operatively (e.g. steroids, procoagulants, adhesion barriers).Finally, the dressing would also present a smooth surface towards thenerve root during the immediate post-operative period.

This neuroforaminal compression dressing may, for example, comprise theoptional protective sheath, percutaneously held tightly in place againstthe abraded surface. Alternatively or additionally, a separatepercutaneously removable compression dressing may be placed followingtissue abrasion, with or without a biodegradable component. In a furtheralternative embodiment, an entirely biodegradable compression dressingmay be placed tightly against the abraded surface, with the compressiondressing remaining completely implanted following the procedure.

Safe tissue removal, ablation and remodeling with these methods anddevices are further enabled by complementary methods and apparatusesthat assist with accurate neural localization. Neural localization willbe performed by neural stimulation through electrically conductivematerials located within the capped epidural needle tip; within theepidural tools that will be in contact with tissue to be modified; orone or both sides of the working barrier. Neural stimulation will beperformed in conjunction with monitoring of the patient for sensoryand/or motor response to the electrical impulses.

Said backstop may also contain neural localization capabilities,including a conductive element on the working side and/or thenon-working side. The conductive element may be used to ensure that theneural and their adjacent vascular structures are on the non-workingside of the barrier. In the instance that the barrier is placed throughthe lateral recess or neural foramina, appropriate low intensityelectrical stimulation on the non-working surface should result in thestimulation of sensory or motor nerves in the patient's extremity, whileappropriate electrical conduction on the working surface should resultin no neural stimulation. Neural stimulation may be monitored bymonitoring somatosensory-evoked potentials (SSEPs), motor-evokedpotentials (MEPs), and/or by looking for visual signs of muscularcontraction within the extremities. (Somatosensory evoked potentials(SSEPs) are non-invasive studies performed by repetitive, sub-maximal,electrical stimulation of a sensory or mixed sensory and motor nerve. Inresponse to the nerve stimulation the brain generates cerebral actionpotentials (electrical waves), that can be measured and recorded overthe scalp and spine with surface electrodes. In many cases, needleelectrodes are used for intraoperative SSEP monitoring, as they requireless current, and reduce artifact. The recorded response is a series ofwaves that reflect activation of neural structures.) SSEP, SEP, MEP orEMG feedback may be monitored and/or recorded visually, or may bemonitored audibly, potentially conveying quantitative feedback relatedto the volume or frequency of the auditory signal (e.g., a Geigercounter type of quantitative auditory feedback). Intensity of signal orstimulation may be monitored and used to localize the nerve duringplacement, as well.

For example, the surgeon may use the neural stimulator to ensure thatthere is not stimulation of vulnerable neurons on the working side ofthe barrier, prior to initiating tissue manipulation with the workingtools. For example, with the barrier in position in the lateral recessor neural foramina, the surgeon may send electrical current first alongthe working side of the barrier, then along the backside of the barrier.Low level stimulation of the working side would be expected to result inno neural stimulation, while the same stimulation on the backside of thebarrier would be expected to stimulate dorsal roots, nerve roots, organglia.

Neural localization may be further enabled by the addition of surgicalinstruments (e.g. cautery devices, graspers, shavers, burrs, probes,etc.) that are able to selectively stimulate electrically whilemonitoring nerve stimulation in similar fashions. Quantification ofstimulation may enable neural localization. For instance, one might usea calibrated sensor input that recognizes stronger stimulation as thedevice is closer the neural structures. For added safety, a surgicaldevice may be designed to automatically stimulate before or duringresection, and may even be designed to automatically stop resection whennerve stimulation has been sensed.

A method for modifying spinal anatomy is disclosed. The method includesdelivering a surgical apparatus to an epidural space and surgicallyaltering tissues that impinge neural or vascular structures in thelateral recess, neural foramina or central canal of the spine with theapparatus. Surgically altering tissues can include ablating tissue,resecting tissue, removing tissue, abrading tissue, retracting tissue,stenting tissue, retaining tissue, or thermally shrinking tissue.Surgically altering tissues can additionally include enlarging thelateral recess, neural foramina or central canal of the spine.

Delivering the surgical apparatus to an epidural space can includedelivering an epidural needle to the epidural space, and enlarging thelateral recess, neural foramina or central canal of the spine caninclude focally altering tissue with tools delivered through theepidural needle. Delivering the surgical apparatus to an epidural spacealso can include delivering an epidural needle to the epidural space,and enlarging the lateral recess, neural foramina or central canal ofthe spine also can include focally altering tissue with tools deliveredthrough a working channel disposed adjacent to the epidural needle.

Delivering the surgical apparatus can include converting the epiduralneedle to an endoscope within the epidural space. Delivering thesurgical apparatus to an epidural space also can include delivering aworking endoscope to the epidural space, and enlarging the lateralrecess, neural foramina or central canal of the spine can also includefocally altering tissue with tools delivered through the workingendoscope. Delivering the surgical apparatus can also include convertingthe epidural needle into a blunt tipped instrument after placement ofthe needle's tip within the epidural space. Converting the epiduralneedle can also include threading an epidural catheter through theepidural needle into the epidural space, and covering the needle's tipwith an epidural needle cover delivered via the catheter.

Delivering the surgical apparatus can also include converting theepidural needle into an endoscope via a visualization element disposedwithin the epidural catheter. Delivering the surgical apparatus caninclude infusing fluid into the epidural space to improve visualization.Delivering the surgical apparatus can include inserting a removableworking channel alongside the surgical apparatus. Delivering thesurgical apparatus can include inserting a distal tip of a dual lumenedepidural needle into the epidural space and using at least one of thedual lumens as a working channel for the delivery of instruments intothe epidural space. Delivering the surgical apparatus can includeinserting an instrument chosen from the group consisting of a tissuecauterization tool, a tissue laser device, a radiofrequency deliverydevice, a ronguer, a tissue grasper, a tissue rasp, a probe, a bonedrill, a tissue shaver, a burr, a tissue sander and combinations thereofthrough the surgical apparatus.

Delivering the epidural needle can include inserting the epidural needleto a position with a tip of the needle in proximity to where treatmentwill be directed. Delivering the epidural needle can include insertingthe epidural needle at an interspace below the level of the spine wherethe treatment will be directed.

Delivering surgical apparatus can include delivering the apparatus viaan open surgical route. Delivering the epidural needle can includedelivering the needle via a posterior, interlaminar percutaneous route.Delivering the epidural needle can include delivering the needle via aposterior, translaminar, percutaneous route. Delivering the epiduralneedle can include delivering the needle via a posterior, midline,interspinous, percutaneous route. Delivering the epidural needle caninclude delivering the needle via a percutaneous route through theneural foramen from its lateral aspect. Enlarging can include placing amechanical barrier or backstop between tissue to be resected andadjacent neural or vascular structures. The barrier can be steerable.

The method of modifying the spinal anatomy can include confirming properplacement of the surgical apparatus. Confirming proper placement caninclude confirming proper placement with a nerve stimulator. Confirmingproper placement with a nerve stimulator further comprises confirmingproper placement with stimulation leads placed on a tissue remodelingside of the surgical apparatus. The method of modifying the spinalanatomy can include confirming proper placement of the surgicalapparatus or barrier with a nerve stimulator having stimulation leadsplaced on a tissue remodeling side of the barrier or on a back side ofthe barrier.

The method of modifying the spinal anatomy can include monitoring nervestimulation with the nerve stimulator via somatosensory evokedpotentials (SSEPs). The method of modifying the spinal anatomy caninclude monitoring nerve stimulation with the nerve stimulator via motorevoked potentials (MEPs). The method of modifying the spinal anatomy caninclude monitoring nerve stimulation with the nerve stimulator via motorevoked patient movement. The method of modifying the spinal anatomy caninclude monitoring nerve stimulation via verbal patient sensory responseto the nerve stimulator.

The method of modifying the spinal anatomy can include monitoringenlargement via imaging. The method of modifying the spinal anatomy caninclude surgically altering the tissues under fluoroscopic imaging, MRIimaging, CT imaging, ultrasound imaging, radiological imaging, surgicaltriangulation, infrared or RF surgical triangulation.

The method of modifying the spinal anatomy can include placing anelement that provides tissue compression of surgically remodeled tissueor bone surface in order to enlarge the neural pathway or foraminapost-surgical enlargement. The method of modifying the spinal anatomycan include placing an element that provides tissue compression andretention in order to remodel tissue or bone surface in order to enlargethe neural pathway or foramina de novo. Placing the element can includeplacing the element using a percutaneous technique via the epiduralspace, through a neural foramen at a level to be treated for spinalstenosis, and around a facet complex or a lamina adjacent to the facetcomplex. The method of modifying the spinal anatomy can includetightening the element to a determined tension. Placing the element caninclude placing an element having a posterior anchor that is a cord ortie looped through a hole that has been drilled in the cephalad laminaof the immediately adjacent vertebrae. The method of modifying thespinal anatomy can include tensioning the element to a determined levelvia a tension gauge or other measurement device element holding tensionagainst the tissue to be remodeled.

The method of modifying the spinal anatomy can include releasing abiologically active material for the purposes of decreasinginflammation, or promoting remodeling of soft tissue or bone growth fromthe element.

Apparatus for focal tissue alteration are disclosed herein. Theapparatus have an element configured for placement into an epiduralspace, and surgical tools configured for delivery through the elementinto the epidural space to remodel spinal anatomy that impinges uponneural, neurovascular or tendon structures. The element can include anepidural needle, and wherein the surgical tools further comprise atissue remodeling device configured for placement via the epiduralneedle.

The epidural needle can be configured for placement into the epiduralspace via an approach chosen from the group consisting of a posteriorinterspinal midline approach, a posterior paramedian interlaminarapproach, a posterior translaminar paramedian approach through a hole inthe lamina, a neural foramina approach around an anterior border of afacet joint, and combinations thereof. The epidural needle can includetwo adjacent lumens, the second lumen configured to act as a workingchannel for the delivery of the surgical tools into the epidural space.

The apparatus can have an epidural catheter configured to convert theepidural needle into a blunt tipped instrument via an epidural needletip cover that may be opened and then pulled back to cover the needle'stip. The epidural catheter can have a fiberoptic cable forvisualization. The apparatus can have an insertable and removableworking channel for tool access configured for placement alongside theneedle.

The tissue remodeling device can be chosen from the group consisting ofa tissue cauterization tool, a tissue laser device, a radiofrequencydelivery device, a ronguer, a tissue grasper, a tissue rasp, a probe, abone drill, a tissue shaver, a burr, a tissue sander, and combinationsthereof.

The surgical tools can produce nerve stimulation. The apparatus can havea device for monitoring neural stimulation to identify when a workingsurface of the surgical tools is in close proximity to vulnerable neuraltissue during tissue remodeling.

An apparatus for protecting adjacent structures during remodeling ofspinal anatomy that impinges upon neural, neurovascular or tendonstructures is disclosed. The apparatus has a mechanical barrierconfigured for placement between tissue to be resected and the adjacentstructures. The mechanical barrier can be configured for insertionthrough an open incision. The mechanical barrier can be configured forinsertion through a working channel of an endoscope.

The apparatus can be configured for use with a visualization element.The visualization element can be chosen from the group consisting of anepidural endoscope, a fluoroscope, ultrasound, XRay, MRI andcombinations thereof. The apparatus can have a nerve stimulator tofacilitate proper placement of the barrier. A conductive element can beincluded on a tissue modification side of the barrier or on a backsideof the barrier to facilitate nerve localization. A working surface ofthe tissue remodeling device can have neurostimulation capabilities,thereby allowing for a positive and negative control in localizingneural tissue prior to tissue removal.

The apparatus can include a monitoring technique for monitoringelectrical nerve stimulation. The monitoring technique can be chosenfrom the group consisting of SSEPs (somatosensory evoked potentials);MEPs (motor evoked potentials); EMG; verbal inquiries of the patient'ssensory experience to the electrical stimulation; visual techniques,mechanical techniques, tactile techniques monitoring neuro muscularstimulation and movement, and combinations thereof.

The apparatus can include an element configured to provide tissuecompression against surgically remodeled tissue or bone surface in aneural pathway or foramina post-enlargement. The element is configuredfor percutaneous placement via the epidural space, through theneuroforamen at the level to be treated for spinal stenosis, and aroundthe facet complex or the lamina adjacent to the facet complex. Theelement is configured to release a biologically active material for thepurposes of decreasing inflammation, or promoting remodeling of softtissue or bone growth.

The apparatus can be configured for tightening to a determined tensionfor purposes of relieving spinal stenosis. The element can include aposterior anchor having a cord or tie looped through a hole that hasbeen drilled in the cephalad lamina of the immediately adjacentvertebrae. Tension of the element is configured to be set at adetermined level by a tension gauge, or other measurement device elementholding tension against tissue to be remodeled.

The apparatus can have a neuro foraminal compression element configuredto retract and hold pressure on spinal tissue when placed under tension,in order to relieve pressure on impinged neural and vascular structuresand promote tissue remodeling. The apparatus can have a tensioningdevice for the neuro foraminal compression element configured to securetwo ends of the element together at a posterior aspect of the vertebrallamina at a desired tension by pulling the element to the desired levelof tension prior to locking the opposite ends of the element together atsaid tension.

The apparatus can have a tensioning device configured to tighten a loopformed by the neuro foraminal compression element around the facet jointcomplex, within the lateral aspect of the lamina, and configured totighten the compression element across a locking or crimping element toa specified tension, pulling the ligamentum flavum posteriorly in thespinal canal, in the lateral recess and in the neural foramen.

The apparatus can have a tensioning device configured to tighten a loopformed by the neural foraminal compression element around the lamina,close to a facet joint complex, within a lateral aspect of the lamina,and configured to tighten the compression element across a locking orcrimping element to a specified tension, pulling the ligamentum flavumposteriorly in the spinal canal, in the lateral recess and in the neuralforamen.

At least one free end of the neural foraminal compression element can beconfigured for subcutaneous placement to facilitate future removal ofthe element. The compression element can be biodegradable.

The compression element can contain a therapeutic agent chosen from thegroup consisting of medications, bioactive compounds, steroids, depotsteroids, anti-inflammatories, and combinations thereof. The agent canbe configured for immediate release. The agent can be configured forsustained local delivery.

A method of altering bone or soft tissue in a patient is disclosed. Themethod includes placing a tissue abrasion device through tissue to bealtered, holding the tissue abrasion device under tension to bring anabrasive surface of the device firmly against the tissue to be altered,and sliding the abrasive surface of the abrasive element against thetissue to be altered, thereby altering bone or soft tissue immediatelyadjacent to the abrasive surface. Altering can include abrading,removing, or remodeling. Placing the tissue abrasion device throughtissue to be altered can include placing the device through spinaltissue that impinges on neural, neurovascular or ligamentous structuresin the patient's spine. Placing the tissue abrasion device can includeplacing the tissue abrasion device through a neural, neurovascular, orligamentous pathway within the patient's spine, holding the tissueabrasion device under tension to bring the abrasive surface againsttissue within the pathway, and where sliding includes enlarging thepathway via frictional abrasion of the tissue. Placing a tissue abrasiondevice through the pathway can include placing the tissue abrasiondevice through neural foramina of the patient's spine and around theanterior border of a facet joint. Placing the tissue abrasion devicethrough neural foramina of the patient's spine and around the anteriorborder of a facet joint can include placing the device via a routechosen from the group consisting of an open surgical approach, apercutaneous approach, a posterior percutaneous approach, aninterlaminar percutaneous approach, a translaminar percutaneousapproach, an interspinous percutaneous approach, through the neuralforamen from a lateral direction, and combinations thereof. Placing thetissue abrasion device can include placing the device within aprotective sheath or cover.

The method can include altering spinal tissues that impinge on neural,neurovascular, or ligamentous structures in the patient's spine.

Enlarging the pathway can include enlarging a diseased pathway withinthe patient's spine.

Holding the tissue abrasion device under tension against tissue withinthe pathway can include placing an abrasive surface of the tissueabrasion device against tissue chosen from the group consisting of ananterior surface of facet joint capsule, a medial surface of facet jointcapsule, a superior articular process of the facet joint, ligamentumflavum, tissues attached to ligamentum flavum, extruded spinal discmaterial, scar tissue, and combinations thereof.

Sliding the tissue abrasion device against the tissue can includesliding the abrasive surface of the tissue abrasion device against thetissue. Sliding the abrasive surface can include enlarging the lateralrecess, neural foramina or central spinal canal via frictional abrasion.Sliding the abrasive surface can include preferentially abrading tissuechosen from the group consisting of ligamentum flavum, bone spurs, facetcapsule, superior articular process, extruded spinal disc material, scartissue and combinations thereof that impinge on neural or vascularstructures.

The method can include confirming proper placement of the tissueabrasion device. Confirming proper placement of the device can includeconfirming proper placement with a nerve stimulator. Confirming properplacement with a nerve stimulator can include confirming properplacement with a nerve stimulator having stimulation leads placed at alocation chosen from the group consisting of a non-abrasive side of thetissue abrasion device, a back side of a protective sleeve or coverplaced over the tissue abrasion device, an abrasive side of the tissueabrasion device, a working side of the tissue abrasion device, andcombinations thereof. Confirming proper placement can include confirmingplacement via a modality chosen from the group consisting offluoroscopic, MRI, CT, infrared, ultrasound imaging, surgicaltriangulation, and combinations thereof.

The method can include monitoring nerve stimulation viasomatosensory-evoked potentials (SSEPs) with the nerve stimulator. Themethod can include monitoring nerve stimulation via motor-evokedpotentials (MEPs) with the nerve stimulator. The method can includemonitoring nerve stimulation via verbal patient sensory response to thenerve stimulator.

The method can include replacing the tissue abrasion device with acompression element that is held against altered tissue or bone.

Apparatus for the removal of impinging soft tissue or bone within apatient are disclosed. The apparatus can have a tissue abrasion deviceconfigured for placement through impinged tissue pathways. The tissueabrasion device can have an abrasive surface configured for placementadjacent to the impinging tissue. The impinged tissue pathways can havepathways chosen from the group consisting of neural pathways,neurovascular pathways, ligamentous pathways, and combinations thereof.The tissue abrasion device can be configured for the removal of spinalstructures that impinge neural or neurovascular tissues within thepatient, and wherein the tissue abrasion device is configured forplacement through neural foramina of the patient's spine and around theanterior border of a facet joint.

The apparatus can have a protective cover disposed about the tissueabrasion device, where the protective cover is configured to limitexposure of an abrasive surface of the device to areas where tissueremoval is desired. The apparatus can have a nerve stimulator incommunication with the tissue abrasion device to facilitate properplacement of the device.

The apparatus can have a conductive element disposed on an abrasivesurface of the device to enable nerve localization by sending a smallelectrical current through the conductive element.

The apparatus can have an epidural needle, where the tissue abrasiondevice is configured for placement through the epidural needle.

The apparatus can have a visualization element for direct visualizationof the neural foramina. The apparatus can have a neural foraminacompression element.

The compression element can be configured to promote hemostasis anddesired tissue remodeling during healing. The element can be configuredto be left in place after being secured with adequate tension againsttissue abraded with the tissue abrasion device. The compression elementcan be configured to protect a tissue surface abraded with the device.The compression element can be configured to prevent adhesions duringhealing. The compression element can be configured to protect vulnerablestructures adjacent to tissue abraded with the tissue abrasion devicefrom an inflammatory response triggered by tissue abrasion.

The tissue abrasion device can be configured for placement in front of,across, and then behind tissue to be abraded, such as through anaturally occurring or artificially created anatomical foramen or tissuepathway. The abrasive surface can be disposed on all or part of one sideof the tissue abrasion device. The abrasive surface can be disposed onan element chosen from the group consisting of a length of ribbon,strap, cable, belt, cord, string, suture, wire and combinations thereof.The ends of the device can be configured for manual grasping. Theapparatus can have a handle to which ends of the device are attached formanual grasping. The device can be configured for attachment to anelectromechanical power-driven device.

The device can be configured to be placed under tension in order tobring the abrasive surface into contact with tissue to be removed. Theabrasive surface can be configured to be pulled against tissue to beremoved. The abrasive device can have multiple abrasive elements withdifferent abrasive surfaces, configured for interchangeable use. Themultiple abrasive elements can have varying grades of abrasive material.The multiple abrasive elements can have different grooves, patterns ofgrooves, or material patterns on the abrasive surface to facilitatepreferential abrasion of tissue at desired locations. The patterns ofgrooves can have diagonal parallel grooves that preferentially move theabrasive element towards one direction on the surface being abraded asthe abrasive element is pulled in one direction, and towards an opposingdirection as the abrasive element is pulled in a second direction. Themultiple abrasive elements can have different shapes that guide theextent and location of tissue removal.

The apparatus can be configured to carry debris away from the site oftissue removal.

The tissue abrasion device can vary in profile along its length. Thetissue abrasion device can have openings that facilitate passage ofdebris behind the device for storage or removal.

The apparatus can have a monitor for monitoring electrical nervestimulation with the nerve stimulator. The monitor can be configured tomonitor a feedback chosen from the group consisting of SSEPs, MEPs, EMG,verbal communication of patient sensation, visual monitoring, mechanicalmonitoring, tactile means, monitoring of neuromuscular stimulation andmovement, and combinations thereof.

The compression element can be biodegradable. The compression elementcan contain a therapeutic agent configured for delivery to abradedtissue or adjacent neural and neurovascular structures. The therapeuticagent can be a medication, bioactive compound, steroid, depot steroid,anti-inflammatory, adhesion barrier, procoagulant compound, orcombination thereof.

The protective cover can be attached, external to the patient, to asuspension system that includes elements to firmly and individuallygrasp each end of the cover and hold it in position under tensionagainst the tissue surface to be abraded, with an open portion of thecover exposing the abrasive element directly over tissue to be abraded.The protective cover can be configured to protect a non-abrasive side ofthe tissue abrasion device. The protective cover can have channels alongits lateral aspects for the insertion and sliding of the tissue abrasiondevice. The protective cover can include channels along its lateralaspects for the insertion and sliding of a second protective coverconfigured for placement between an abrasive surface of the tissueabrasion device, and tissue adjacent to tissue to be abraded with theabrasive surface.

Finally, the present invention also describes methods and apparatus thatpromote tissue remodeling, separate from the tissue resection orablation. These devices tightly wrap, retract, or hold in position,under tension, impinging tissues within the spinous posterior elements.

It is expected that the apparatus and methods of the present inventionwill facilitate a minimally invasive approach to the selectiveelimination of pathological spinal tissue, thereby enabling symptomaticrelief in patients suffering from spinal stenosis.

The present invention also described a method for treating spinalstenosis. In some embodiments, the method includes the steps ofadvancing a wire from a first point outside of a patient and through atleast one of the patient's lateral recess, spinal neural foramina, orcentral canal of the spine, around at least part of a target tissue, andpassing the distal end of the wire out of the patient from a secondpoint, whereby both ends of the wire are external to the patient;visually confirming that the spinal nerve nearest the target tissue ispositioned anterior to the path of the wire using an image guidancemember; positioning a tissue modification device adjacent to the targettissue using the wire; and modifying the target tissue with the tissuemodification device.

In some embodiments, the step of visually confirming comprisesvisualizing using an image guidance member configured as a fiberoptic.In some embodiments, the step of visually confirming comprises visuallyusing an image guidance member configured for optical tomography,infrared or ultrasound. In some embodiments, the step of visuallyconfirming comprises visualizing using an image guidance member having atip configured to create a space for improved perspective duringvisualization. In some embodiments, the step of visually confirmingcomprises advancing the image guidance member within the patient'sepidural space along the same pathway through the patient as the wire.

In some embodiments, the step of advancing the wire comprises advancingthe wire from the first point located laterally on the side of thepatient's body so that the wire exits from the second point locateddorsally on the side of the patient's body. In some embodiments, thestep of advancing the wire comprises advancing the wire from the firstpoint located dorsally, on the back of the patient's body so that thewire exits from the second point located laterally on the side of thepatient's body. In some embodiments, the step of advancing the wirecomprises percutaneously advancing the wire.

In some embodiments, the step of modifying the target anatomy tissuecomprises using a tissue modification device selected from the groupconsisting of a radiofrequency device, a rasp, a ronguer, a grasper, aburr, a sander, a drill, a shaver, and an abrasive device.

In some embodiments, the step of visually confirming that the spinalnerves are positioned anterior to the path of the wire comprisesvisually confirming that the pathway of the wire passes posterior to thespinal nerve root or ganglion nearest the pathway of the wire. In someembodiments, the step of visually confirming that the spinal nerves arepositioned anterior to the path of the wire is performed before passingthe distal end of the wire out of the patient from the second point.

In some embodiments, the method further includes the step of advancing atissue access instrument into the patient from the first point towardsthe target tissue; wherein the step of advancing the wire comprisespassing the wire through the tissue access instrument. In someembodiments, the step of visually confirming that the spinal nervenearest the target tissue is positioned anterior to the path of the wirecomprises advancing the image guidance member through the tissue accessinstrument.

In some embodiments, the method includes the steps of advancing aguidewire from a first point outside of a patient, towards a targettissue, through a spinal neural foramina and around at least part of thetarget tissue, and passing the distal end of the guidewire out of thepatient from a second point, whereby both ends of the guidewire areexternal to the patient; advancing an image guidance member towards thetarget tissue along the same pathway through the patient as theguidewire; visually confirming that the pathway of the guidewire throughthe patient passes anterior to the facet joint complex but posterior tothe nerve root or ganglion nearest the target tissue; positioning atissue modification device adjacent to the target tissue using theguidewire; and modifying the target tissue with the tissue modificationdevice.

In some embodiments, the step of visually confirming comprisesvisualizing using an image guidance member configured as a fiberoptic.In some embodiments, the step of visually confirming comprisesvisualizing using an image guidance member having a tip configured tocreate a space for improved perspective during visualization. In someembodiments, the step of advancing the guidewire comprisespercutaneously advancing the guidewire. In some embodiments, the step ofvisually confirming that the pathway of the guidewire through thepatient passes anterior to the facet joint complex but posterior to thenerve root or ganglion nearest the target tissue is performed beforepassing the distal end of the guidewire out of the patient from thesecond point. In some embodiments, the step of advancing the guidewirecomprises advancing a tissue access instrument into the patient from thefirst point towards the target tissue and passing the guidewire throughthe tissue access instrument.

In some embodiments, the method includes the steps of advancing a tissueaccess instrument into the patient from a first point outside of thepatient and towards a spinal neural foramen; advancing a wire throughthe tissue access instrument, towards a target tissue, through thespinal neural foramina and around at least part of the target tissue,and passing the distal end of the guidewire out of the patient from asecond point, whereby both ends of the wire are external to the patient;advancing an image guidance member along the tissue access instrumenttowards the target tissue; visually confirming that the pathway of thewire through the patient passes anterior to the facet joint complex butposterior to the nerve root or ganglion nearest the target tissue;positioning a tissue modification device adjacent to the target tissueusing the guidewire; and modifying the target tissue with the tissuemodification device.

In some embodiments, the method includes the steps of advancing a tissueaccess instrument into the patient from a first point outside of thepatient and towards a spinal neural foramen; visually confirming thatthe pathway of the tissue access instrument through the patient passesanterior to the facet joint complex but posterior to the nerve root organglion nearest the target tissue; advancing a wire through the tissueaccess instrument, towards a target tissue, through the spinal neuralforamina and around at least part of the target tissue, and passing thedistal end of the guidewire out of the patient from a second point,whereby both ends of the wire are external to the patient; positioning atissue modification device adjacent to the target tissue using theguidewire; and modifying the target tissue with the tissue modificationdevice.

In some embodiments, the method further includes the step of advancingan image guidance member along the tissue access instrument towards thetarget tissue.

In various embodiments, the present invention provides methods,apparatus and systems for modifying tissue in a patient. Generally, themethods, apparatus and systems may involve using an elongate, at leastpartially flexible tissue modification device having one or more tissuemodifying members to modify one or more target tissues. The tissuemodification device may be configured such that when the tissuemodification member (or members) is in a position for modifying targettissue, one or more sides, surfaces or portions of the tissuemodification device configured to avoid or prevent damage to non-targettissue will face non-target tissue. In various embodiments, during atissue modification procedure, an anchoring force may be applied at ornear either a distal portion or a proximal portion of the tissuemodification device, either inside or outside the patient. Pulling ortensioning force may also be applied to the unanchored end of the deviceto urge the tissue modifying member(s) against target tissue. The tissuemodifying members may then be activated to modify tissue while beingprevented from extending significantly beyond the target tissue in aproximal or distal direction. In some embodiments, the tissue modifyingmembers may be generally disposed along a length of the tissuemodification device that approximates a length of target tissue to bemodified.

By “applying an anchoring force,” it is meant that a force is applied tomaintain a portion of a device, or the device as a whole, substantiallystable or motion-free. Applying an anchoring force is, therefore, notlimited to preventing all movement of a device, and in fact, a device towhich an anchoring force is applied may actually move in one or moredirections in some embodiments. In other embodiments, an anchoring forceis applied to maintain a portion of a device substantially stable, whileanother portion of the device is allowed to move more freely. As will bedescribed in further detail below, applying an anchoring force in oneembodiment involves a user of a device grasping the device at or nearone of its ends. In other embodiments, devices may use one or moreanchoring members to apply an anchoring force. In a number ofembodiments, an anchoring force may be applied with or against one ormore tissues of a patient's body, and the tissue(s) may often move evenas they apply (or help apply) the force. Thus, again, applying ananchoring force to a device does not necessarily mean that all motion ofthe device is eliminated. Of course, in some embodiments, it may bepossible and desirable to eliminate all movement or substantially allmovement of a device (or portion of a device), and in some embodimentsanchoring force may be used to do so.

Methods, apparatus and systems of aspects of the present inventiongenerally provide for tissue modification while preventing unwantedmodification of, or damage to, surrounding tissues. Tensioning thetissue modification device by applying anchoring force at or near oneend and applying tensioning or pulling force at or near the opposite endmay enhance the ability of tissue modification members of the device towork effectively within a limited treatment space. Applying tensioningforce to a predominantly flexible device may also allow the device tohave a relatively small profile, thus facilitating its use in lessinvasive procedures and in other procedures in which alternativeapproaches to target tissue may be advantageous.

In some embodiments, the described methods, apparatus and systems may beused to modify tissue in a spine, such as for treating neuralimpingement, neurovascular impingement and/or spinal stenosis. Inalternative embodiments, target tissues in other parts of the body maybe modified.

In one aspect of the present invention, a method for preventing unwanteddamage to tissue in a spine of a patient during a tissue modificationprocedure may involve: advancing a distal portion of a delivery deviceinto an epidural space of the patient's spine; exposing at least aportion of at least one barrier member out of the distal portion of thedelivery device, wherein at least a portion of the barrier member ischangeable from a collapsed configuration in the delivery device to anexpanded configuration outside the delivery device; positioning at leastpart of the exposed barrier member between target tissue and non-targettissue in the spine; and performing at least one tissue modificationprocedure on the target tissue, using at least one tissue modificationdevice. In some embodiments, at least part of the barrier member may bedisposed between the tissue modification device and the non-targettissue to prevent unwanted damage to the non-target tissue.

In another aspect of the present invention, a method for preventingunwanted damage to tissue in a spine of a patient during a tissuemodification procedure may involve: advancing at least a distal portionof at least one barrier member over at least one guide member into anepidural space of the patient's spine; positioning at least an expandedportion of the barrier member between target tissue and non-targettissue; and performing at least one tissue modification procedure on thetarget tissue, using at least one tissue modification device. Again, insome embodiments, at least part of the barrier member may be disposedbetween the tissue modification device and the non-target tissue toprevent unwanted damage to the non-target tissue.

In another aspect of the present invention, a method for preventingunwanted damage to tissue of a patient during a tissue modificationprocedure may involve: advancing at least a distal portion of a deliverydevice into the patient and to a position between or adjacent targettissue and non-target tissue; advancing at least a distal portion of atleast one barrier member over at least one guide member to a positionbetween or adjacent target tissue and non-target tissue in the patient;exposing at least a portion of the at least one barrier member out ofthe distal portion of the delivery device, wherein at least a portion ofthe barrier member is changeable from a collapsed configuration in thedelivery device to an expanded configuration outside the deliverydevice; and performing at least one tissue modification procedure on thetarget tissue, using at least one tissue modification device.

In yet another of the present invention, a barrier device for preventingunwanted damage to tissue in a spine of a patient during a tissuemodification procedure may include: at least one shape changing portionchangeable from a collapsed configuration, to facilitate passage intothe spine, to an expanded configuration, to facilitate protection ofnon-target tissue; at least one elongate portion extending beyond theshape changing portion, the elongate portion having a low profile tofacilitate passage of the barrier device into the patient and a lengthsufficient to extend from an opening on the patient's skin to an area ator near the spine; and at least one guide feature extending along atleast a portion of the barrier to allow the barrier to be passed intothe patient over at least one guide member. In some embodiments, thebarrier device may have an overall length sufficient to pass from afirst opening on the patient's skin, into an epidural space of thespine, and between target and non-target tissue.

In another embodiment of the present invention, a barrier device forpreventing unwanted damage to tissue of a patient during a tissuemodification procedure may include: at least one shape changing portionchangeable from a collapsed configuration, to facilitate passage intothe patient, to an expanded configuration, to facilitate protection ofnon-target tissue; at least one elongate portion extending beyond theshape changing portion, the elongate portion having a low profile tofacilitate passage of the barrier device into the patient and a lengthsufficient to extend from an opening on the patient's skin to an area ator near target and non-target tissues; and at least one guide featureextending along at least a portion of the barrier to allow the barrierto be passed into the patient over at least one guide member. In someembodiments, the barrier device may have an overall length sufficient topass from a first opening on the patient's skin and between the targetand non-target tissues.

A system for preventing unwanted damage to tissue in a spine of apatient during a tissue modification procedure may include a barrierdevice, a barrier delivery device for facilitating passage of thebarrier device into the spine, and at least one guide member over whichthe barrier is passable into the spine. In some embodiments, the barriermay include: at least one shape changing portion changeable from acollapsed configuration, to facilitate passage into the spine, to anexpanded configuration, to facilitate protection of non-target tissue;at least one elongate portion extending beyond the shape changingportion, the elongate portion having a low profile to facilitate passageof the barrier device into the patient and a length sufficient to extendfrom an opening on the patient's skin to an area at or near the spine;and at least one guide feature extending along at least a portion of thebarrier to allow the barrier to be passed into the patient over at leastone guide member. In some embodiments, the barrier device may have anoverall length sufficient to pass from a first opening on the patient'sskin, into an epidural space of the spine, and between the target andnon-target tissue.

In one aspect of the present invention, a device for cutting ligamentand/or bone tissue in a lateral recess and/or an intervertebral foramenof a spine of a patient to treat spinal stenosis may include: anelongate shaft having a rigid proximal portion and a distal portionarticulatable relative to the proximal portion; a handle coupled withthe proximal portion of the shaft; a tissue cutter disposed on one sideof the distal portion of the shaft; a first actuator coupling the handlewith the tissue cutter for activating the tissue cutter to cut tissue;and a second actuator coupling the handle with the distal portion forarticulating the distal portion relative to the proximal portion. Insome embodiments, the distal portion of the shaft may be configured topass at least partway into an intervertebral foramen of the patient'sspine.

By “articulatable,” it is meant that the distal portion may be bent,flexed, angled or the like, relative to the proximal portion. In otherwords, for the purposes of this application, “articulate” encompassesnot only to articulate about a joint, but also includes bending, flexingor angling by means of one or more slits, grooves, hinges, joints orother articulating means.

In various alternative embodiments, the distal portion of the shaft ofthe device may be rigid, flexible, or part rigid/part flexible. In someembodiments, the distal portion of the shaft may be configured toarticulate toward the side on which the tissue cutter is disposed. Tomake the distal portion of the shaft articulatable relative to theproximal portion, some embodiments may further include an articulationmember disposed along the shaft between the proximal and distalportions. As mentioned above, such an articulation member may include,for example, one or more slits, grooves, hinges, joints or the like. Inone embodiment, an articulation member may comprise a first materialdisposed on the side of the shaft on which the tissue cutter is disposedand a second material disposed on an opposite side of the shaft, wherethe first material is more compressible than the second material.

In some embodiments, the distal portion of the shaft may be configuredto articulate incrementally from a relatively unflexed position to afirst flexed position and to at least a second flexed position.Optionally, the device may further include a locking mechanism forlocking the distal portion in an articulated position relative to theproximal portion.

Any of a number of different tissue cutters may be used in variousembodiments. For example, examples of tissue cutters which may beincluded in the device in some embodiments include but are not limitedto blades, abrasive surfaces, files, rasps, saws, planes,electrosurgical devices, bipolar electrodes, monopolar electrodes,thermal electrodes, cold ablation devices, rotary powered mechanicalshavers, reciprocating powered mechanical shavers, powered mechanicalburrs, lasers, ultrasound devices, cryogenic devices, and water jetdevices. In one embodiment, for example, the tissue cutter comprises atranslatable blade. In some embodiments, the blade may have a heightgreater than a height of a portion of the shaft immediately below theblade, and a total height of the blade and the portion of the shaftimmediately below the blade may be less than a width of the portion ofthe shaft immediately below the blade. In some embodiments, the tissuecutter may further include a fixed blade fixedly attached to the shaft,and the translatable blade may move toward the fixed blade to cuttissue. In an alternative embodiment, the tissue cutter may furtherinclude a fixed backstop fixedly attached to the shaft, and thetranslatable blade may move toward the fixed backstop to cut tissue.

In some embodiments, the second actuator may include a tensioning wireextending from the handle to the distal portion of the shaft and atensioning member on the handle coupled with the tensioning wire andconfigured to apply tensioning force to the wire. In an alternativeembodiment, the second actuator may include a compression memberextending from the handle to the distal portion of the shaft and a forceapplication member on the handle coupled with the compression member andconfigured to apply compressive force to the compression member. In suchembodiments, the compression member may include, for example, one ormore wires, substrates and/or fluids.

Optionally, in some embodiments the shaft may further include a distaltip articulatable relative to the distal portion of the shaft, and thesecond actuator may extend to the distal tip. The first and secondactuators may have any of a number of different configurations indifferent embodiments, such as but not limited to triggers, squeezablehandles, levers, dials, toggle clamps, toggle switches and/or vicegrips.

In another aspect of the present invention, a device for cutting tissuein a human body may include: an elongate shaft having a rigid proximalportion and a distal portion articulatable relative to the proximalportion; a handle coupled with the proximal portion of the shaft; atranslatable blade slidably disposed on one side of the distal portionof the shaft; a first actuator coupling the handle with the tissuecutter for activating the tissue cutter to cut tissue; a second actuatorcoupling the handle with the distal portion for articulating the distalportion relative to the proximal portion; and a locking mechanismconfigured to lock the distal portion in an articulated configurationrelative to the proximal portion. In some embodiments, the translatableblade may have a height greater than a height of a portion of the shaftimmediately below the blade, and a total height of the blade and theportion of the shaft immediately below the blade may be less than awidth of the portion of the shaft immediately below the blade. Invarious embodiments, the distal portion of the shaft may be rigid,flexible, or part rigid/part flexible.

In another aspect of the present invention, a method for cuttingligament and/or bone tissue in a lateral recess and/or an intervertebralforamen of a spine of a patient to treat spinal stenosis may involve:advancing a distal portion of a tissue cutting device into an epiduralspace of the patient's spine; articulating the distal portion relativeto a proximal portion of the device; advancing the distal portion atleast partway into an intervertebral foramen of the spine; urging atissue cutter disposed on one side of the distal portion of the deviceagainst at least one of ligament or bone tissue in at least one of thelateral recess or the intervertebral foramen; and activating the tissuecutter to cut at least one of the ligament or bone tissue.

In some embodiments, the distal portion may be advanced through anaccess conduit device. In some embodiments, the distal portion may beadvanced through the conduit device and between two adjacent vertebraeinto the epidural space without removing vertebral bone. Articulating,in one embodiment, may involve applying tensioning force to a tensioningmember disposed longitudinally through the device from the proximalportion to the distal portion. Alternatively, articulating may involveapplying compressive force to a compressive member disposedlongitudinally through the device from the proximal portion to thedistal portion. In some embodiments, articulating may involvearticulating to a first articulated configuration before advancing thedistal portion into the foramen and further articulating to a secondarticulated configuration after advancing the distal portion at leastpartway into the foramen. Some embodiments of the method may optionallyfurther include locking the distal portion in an articulated positionrelative to the proximal portion before urging the tissue cutter againsttissue. Such a method may also involve, in some embodiments, unlockingthe distal portion, straightening the distal portion relative to theproximal portion, and removing the tissue cutting device from thepatient.

In some embodiments, urging the tissue cutter against tissue may involveapplying force to a handle of the tissue cutting device. Activating thetissue cutter, in various embodiments, may involve activating one ormore blades, abrasive surfaces, files, rasps, saws, planes,electrosurgical devices, bipolar electrodes, monopolar electrodes,thermal electrodes, cold ablation devices, rotary powered mechanicalshavers, reciprocating powered mechanical shavers, powered mechanicalburrs, lasers, ultrasound devices, cryogenic devices, and/or water jetdevices. For example, in one embodiment, activating the tissue cuttermay involve advancing a translatable blade toward one of a stationaryblade and a backstop. In an alternative embodiment, activating thetissue cutter may involve retracting a translatable blade toward one ofa stationary blade and a backstop. In yet another alternativeembodiment, activating the tissue cutter may involve translating twoblades toward one another.

In one aspect of the present invention, a method for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay involve: percutaneously advancing a distal portion of a tissueremoval cannula into the ligamentum flavum tissue; uncovering aside-opening aperture disposed on the distal portion of the cannula toexpose a tissue cutter disposed in the cannula; and cutting ligamentumflavum tissue using the tissue cutter while the aperture is uncovered.In some embodiments, uncovering the aperture may involve retracting aninner cannula through the tissue removal cannula. Cutting ligamentumflavum tissue may involve cutting tissue using a tissue cutter selectedfrom the group consisting of blades, abrasive surfaces, files, rasps,saws, planes, electrosurgical devices, bipolar electrodes, monopolarelectrodes, thermal electrodes, cold ablation devices, rotary poweredmechanical shavers, reciprocating powered mechanical shavers, poweredmechanical burrs, lasers, ultrasound devices, cryogenic devices, andwater jet devices.

In some embodiments, the ligamentum flavum tissue may be cut using aradiofrequency device, and the method further involves, before theuncovering step, activating the radiofrequency device. In someembodiments, the method may include, before the uncovering step:articulating the distal portion of the cannula relative to the proximalportion; and advancing the articulated distal portion at least partwayinto an intervertebral foramen of the spine. In some embodiment, themethod may further involve extending the cutter out of the aperturebefore the cutting step.

Optionally, the method may include removing the cut ligamentum flavumtissue through the cannula. In some embodiments, removing the cut tissuecomprises applying suction to the cannula. In some embodiments, removingthe cut tissue includes: engaging the cut tissue with the tissue cutteror a separate tissue engaging member; and retracting the tissue cutteror tissue engaging member through the cannula. Some embodiments mayfurther involve introducing a substance through the side-facing apertureof the cannula, the substance selected from the group consisting of ahemostatic agent, an analgesic, an anesthetic and a steroid.

Optionally, some embodiments of the method may include, before thecutting step: activating a nerve stimulator coupled with the distalportion of the cannula; and monitoring for response to the activation.Some embodiments of the method may also include deploying a shieldbetween the cannula and non-target tissue before the cutting step. Inone embodiment, the method may also include, before the cutting step:activating a nerve stimulator coupled with the shield; and monitoringfor response to the activation.

In another aspect of the present invention, a method for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay involve: percutaneously advancing a distal portion of a tissueremoval cannula into the ligamentum flavum tissue; activating at least afirst nerve stimulator coupled with the distal portion of the cannula;monitoring for response to the activation; uncovering a side-openingaperture disposed on the distal portion of the cannula to expose atissue engaging member disposed in the cannula; engaging ligamentumflavum tissue with the tissue engaging member; and cutting ligamentumflavum tissue with a tissue cutter disposed in or on the cannula.

In some embodiments, the method may include, before the uncovering step:activating at least a second nerve stimulator coupled with the distalportion of the cannula apart from the first nerve stimulator; monitoringfor response to activation; and comparing an amount of activationrequired to illicit a response using the first nerve stimulator with anamount of activation required to illicit a response using the secondnerve stimulator. In some embodiments, cutting the ligamentum flavumtissue may involve advancing an inner cannula having a sharp distal endand disposed around the tissue engaging member and within the tissueremoval cannula.

In another aspect of the present invention, a method for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay involve: coupling a flexible distal portion of a tissue removalcannula with one end of a guidewire; pulling the flexible distal portioninto the ligamentum flavum tissue by pulling the guidewire; uncovering aside-opening aperture disposed on the distal portion of the cannula toexpose a tissue cutter disposed in the cannula; and cutting ligamentumflavum tissue using the tissue cutter.

In some embodiments, the method may further include applying tensioningforce to the tissue removal cannula and the guidewire, before thecutting step, to urge the aperture against the ligamentum flavum tissue.The method may optionally further involve, before the cutting step:activating a nerve stimulator coupled with the distal portion of thecannula; and monitoring for response to the activation. In someembodiments, the method may also include deploying a shield between thecannula and non-target tissue before the cutting step. Optionally, themethod may include, before the cutting step: activating a nervestimulator coupled with the shield; and monitoring for response to theactivation.

In another aspect of the present invention, a method for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay involve: percutaneously advancing a distal portion of a tissueremoval device into at least one of an epidural space or a ligamentumflavum of the spine; activating an energy delivery member disposed on orin the distal portion of the tissue removal device; and cuttingligamentum flavum tissue with the activated energy delivery member.

In some embodiments, advancing the distal portion may involve pullingthe distal portion behind a guidewire. In some embodiments, the distalportion may be advanced at least partway into an intervertebral foramenof the spine. In some embodiments, the distal portion of the tissueremoval device may be flexible. In some embodiments, a proximal portionextending proximally from the distal portion of the tissue removaldevice may be flexible. In some embodiments, activating the energydelivery member may involve activating a member selected from the groupconsisting of electrosurgical devices, bipolar electrodes, monopolarelectrodes, thermal electrodes, cold ablation devices, lasers,ultrasound devices and cryogenic devices. In some embodiments, cuttingthe tissue involves retracting the energy delivery member throughtissue. In some embodiments, cutting the tissue may involve advancingthe energy delivery member through tissue. Some embodiments may furtherinvolve extending the energy delivery member out of the tissue removaldevice before the cutting step. Some embodiments may further involveremoving the cut ligamentum flavum tissue through a lumen in the tissueremoval device. In some embodiments, removing the cut tissue may involveapplying suction to the tissue removal device. In some embodiments,removing the cut tissue may involve: engaging the cut tissue with theenergy delivery member or a separate tissue engaging member; andretracting the energy delivery member or tissue engaging member throughthe tissue removal device.

Some embodiments may further involve introducing a substance through anaperture in the tissue removal device, the substance selected from thegroup consisting of a hemostatic agent, an analgesic, an anesthetic anda steroid. Some embodiments may involve, before the cutting step:activating at least a first nerve stimulator coupled with the distalportion of the tissue removal device; and monitoring for response to theactivation. Some embodiments may involve, before the cutting step:activating at least a second nerve stimulator coupled with the distalportion of the tissue removal device apart from the first nervestimulator; monitoring for response to activation; and comparing anamount of activation required to illicit a response using the firstnerve stimulator with an amount of activation required to illicit aresponse using the second nerve stimulator. Optionally, the method mayalso involve automatically deactivating the energy delivery member ifthe response to activation by the nerve stimulator(s) indicates that theenergy delivery member is in contact with or near nerve tissue. Themethod may also include repeating the activating and monitoring stepsduring the cutting step; and repeating the automatic deactivating stepwhenever the response to activation indicates that the energy deliverymember is in contact with or near nerve tissue. In one embodiment, themethod may include deploying a shield between the cannula and non-targettissue before the cutting step. Such a method may also include, beforethe cutting step: activating at least a first nerve stimulator coupledwith the shield; and monitoring for response to the activation. Such amethod may also include, before the cutting step: activating at least asecond nerve stimulator coupled with the shield apart from the firstnerve stimulator; monitoring for response to activation; and comparingan amount of activation required to illicit a response using the firstnerve stimulator with an amount of activation required to illicit aresponse using the second nerve stimulator. In some embodiments, themethod also may include automatically deactivating the energy deliverymember if the response to activation by the nerve stimulator(s)indicates that the energy delivery member is in contact with or nearnerve tissue. In one embodiment, the method may also include: repeatingthe activating and monitoring steps during the cutting step; andrepeating the automatic deactivating step whenever the response toactivation indicates that the energy delivery member is in contact withor near nerve tissue.

In another aspect of the present invention, a device for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay include: a cannula having a proximal end, a tissue-penetratingdistal end, and a side-facing aperture closer to the distal end than theproximal end; an aperture cover slidably coupled with the cannula andconfigured to advance and retract to cover and uncover the aperture; anda tissue cutter slidably disposed within the cannula and configured toextend through the aperture to cut ligamentum flavum tissue. In someembodiments, the aperture cover may comprise an inner cannula slidablydisposed in the tissue removal cannula. In some embodiments, a distalportion of the cannula may be articulatable relative to a proximalportion of the cannula.

In various embodiments, the tissue cutter may be selected from the groupconsisting of blades, abrasive surfaces, files, rasps, saws, planes,electrosurgical devices, bipolar electrodes, monopolar electrodes,thermal electrodes, cold ablation devices, rotary powered mechanicalshavers, reciprocating powered mechanical shavers, powered mechanicalburrs, lasers, ultrasound devices, cryogenic devices, and water jetdevices. In some embodiments, the tissue cutter may be configured toextend out of the aperture. In some embodiments, the tissue cutter maybe configured to engage cut ligamentum flavum tissue and to be retractedthrough the cannula to remove the engaged tissue.

Optionally, the device may also include a suction connector for couplingthe proximal end of the cannula with a suction device for removing cuttissue through the cannula. Also optionally, the device may include atleast a first nerve stimulator coupled with the cannula at or near theaperture. Such a device may also include at least a second nervestimulator coupled with the cannula, where the first nerve stimulator isdisposed generally on the same side of the cannula as the aperture andthe second nerve stimulator is disposed between about 90 degrees andabout 180 degrees away from the first stimulator along a circumferenceof the cannula. Some embodiments may also include a shield coupled withthe cannula for preventing the cutter from contacting non-target tissue.

In another aspect of the present invention, a device for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay include: a cannula having a proximal end, a tissue-penetratingdistal end, and a side-facing aperture closer to the distal end than theproximal end; a tissue-engaging member disposed within the cannula andadapted to engage tissue via the aperture; an aperture cover slidablycoupled with the cannula and configured to advance and retract to coverand uncover the aperture, the cover having a sharp, tissue cutting edgeto cut tissue engaged by the tissue-engaging member; and a nervestimulation member coupled with the cannula adjacent or near theaperture. In some embodiments, a distal portion of the cannula may bearticulatable relative to a proximal portion of the cannula. In variousembodiments, the tissue-engaging member is selected from the groupconsisting of needles, hooks, blades, teeth and barbs. Thetissue-engaging member may be slidably disposed within the cannula suchthat it can be retracted through the cannula to remove cut tissue fromthe cannula.

The aperture cover may comprise an inner cannula slidably disposed inthe outer cannula. Optionally, the device may include a suctionconnector for coupling the proximal end of the cannula with a suctiondevice for removing cut tissue through the cannula. Some embodiments mayalso include at least a second nerve stimulator coupled with the cannulaapart from the first nerve stimulator. The device may further include ashield coupled with the cannula for preventing the cutter fromcontacting non-target tissue. The device may optionally further includea nerve stimulator coupled with the shield.

In another aspect of the present invention, a device for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay include: an elongate body having a proximal portion, a flexibledistal portion, and a side-facing aperture disposed on the distalportion, wherein the distal portion is configured to be passedpercutaneously into at least one of an epidural space or a ligamentumflavum of the spine; and an energy delivery member disposed within theelongate body and configured to extend through the aperture to cutligamentum flavum tissue. In some embodiments, the proximal portion ofthe body may be at least partially flexible. Alternatively, the proximalportion of the body may be rigid. In some embodiments, the distalportion of the body may be configured to be passed at least partway intoan intervertebral foramen of the spine.

The device may further include a guidewire coupling member disposed onthe distal portion of the elongate body for pulling the distal portioninto the spine. In some embodiments, the energy delivery member may beselected from the group consisting of electrosurgical devices, bipolarelectrodes, monopolar electrodes, thermal electrodes, cold ablationdevices, lasers, ultrasound devices and cryogenic devices. In someembodiments, the energy delivery member may be slidably disposed withinthe elongate body and is configured to be advanced through the aperture.In one embodiment, the energy delivery member may comprise a wire loopelectrode. In some embodiments, the elongate body may further include alumen through which cut ligamentum flavum tissue may be removed.

Some embodiments may further include a suction device couplable with theelongate body for removing the cut ligamentum flavum tissue through thelumen. Some embodiments may further include an irrigation devicecouplable with the elongate body for passing fluid through the lumen.Some embodiments may further include a substance disposed in the lumenfor delivery through the aperture, where the substance may be selectedfrom the group consisting of a hemostatic agent, an analgesic, ananesthetic and a steroid.

The device may optionally include at least a first nerve stimulatorcoupled with the distal portion of the elongate body. In someembodiments, the device may also include at least a second nervestimulator coupled with the distal portion of the elongate body apartfrom the first nerve stimulator. The device may also include means fordetecting stimulation of a nerve. The device may also include means forautomatically deactivating the energy delivery member if the means fordetecting stimulation indicates that the energy delivery member is incontact with or near nerve tissue.

In some embodiments, the device may include a shield coupled with theelongate body for preventing the energy delivery member from contactingnon-target tissue. In some embodiments, the device may include at leasta first nerve stimulator coupled with the shield. The device may alsoinclude at least a second nerve stimulator coupled with the shield apartfrom the first nerve stimulator. Optionally, the device may includemeans for detecting stimulation of a nerve. The device may also includemeans for automatically deactivating the energy delivery member if themeans for detecting indicates that the energy delivery member is incontact with or near nerve tissue.

In another aspect of the present invention, a system for percutaneouslyremoving ligamentum flavum tissue in a spine to treat spinal stenosismay include: a tissue removal device, comprising: an elongate bodyhaving a proximal portion, a flexible distal portion, and a side-facingaperture disposed on the distal portion, wherein the distal portion isconfigured to be passed percutaneously into at least one of an epiduralspace or a ligamentum flavum of the spine; and an energy delivery memberdisposed within the elongate body and configured to extend through theaperture to cut ligamentum flavum tissue; and an energy source removablycouplable with the tissue removal device for supplying energy to theenergy delivery member. The tissue removal device may include any of thefeatures and configurations described above.

Optionally, the system may also include a guidewire configured to couplewith the guidewire coupling member. The system may further include ahandle removably couplable with the guidewire for pulling the guidewirefrom outside a patient. In some embodiments, the energy delivery membermay be selected, for example, from the group consisting ofelectrosurgical devices, bipolar electrodes, monopolar electrodes,thermal electrodes, cold ablation devices, lasers, ultrasound devicesand cryogenic devices. In some embodiments, the energy source may beselected from the group consisting of a radiofrequency device, a heatingdevice, a cooling device, a cryogenic device, a laser and an ultrasoundgenerator.

The system may optionally further include a suction device for removingthe cut ligamentum flavum tissue through the lumen. The system mayoptionally include an irrigation device for passing fluid through thelumen. The system may further include a substance disposed in the lumenof the tissue removal device for delivery through the aperture, whereinthe substance is selected from the group consisting of a hemostaticagent, an analgesic, an anesthetic and a steroid.

The system may further include one or more nerve stimulation members,such as those described above. Optionally, the system may include meansfor detecting stimulation of a nerve. In some embodiments, the systemmay automatically deactivate the tissue removal device when nervestimulation is detected. In some embodiments, nerve stimulators may bepowered by the energy source, and means for detecting stimulation andthe means for automatically deactivating the energy delivery member arecoupled with the energy source.

Described herein are methods, devices and systems for measuring the sizeof a compliant region adjacent to a patient's nerve root. In particular,these devices, systems and methods may be used to measure theintervertebral foramen, and/or the lateral recess and/or the centralcanal of the spine. These measurements may be made to determine the sizeof spacing around the nerve root. The space adjacent or around the nerveroot may be referred to as the compliant region. The methods, devicesand systems for measuring this compliant region may be used as part of adecompression procedure in which impingement is reduced. Thus, thesemeasurements may help gage the degree of impingement (or reduction ofimpingement) on the nerve root. The greater the compliant region, theless impingement. The compliant space adjacent to the nerve root may befilled with tissue (particularly soft tissues) or may be empty space.The compliant space is typically surrounded by non-compliant tissue(such as bone), forming the lateral recess, intervertebral foramina andcentral canal. The measurement devices and systems described herein aretypically configured to be used in conjunction with a guidewire, so thatthey can be advanced in to the intervertebral foramen, lateral recessand/or central canal after placement of a guidewire through theintervertebral foramen. For example, the devices described herein may beconfigured to attach to the proximal end of a guidewire so that they canbe pulled at least partially through the intervertebral foramen. Themeasurement device may be expandable, inflatable, calibrated to a knownsize and/or shape, moldable, or some combination of these. Themeasurement devices may include neural stimulation, which may be used toconfirm the position of the device, and/or may be used to determine thedimension of the intervertebral foramen, lateral recess and/or centralcanal. Any of the devices described herein may form part of a system fortreating a spine, or a system for measuring an intervertebral foramen.For example, a system for treating a spine may include a guidewire andany of the measurement devices described.

Also described herein are methods of measuring the size of a compliantregion adjacent to a patient's nerve root. For example, the method maybe used to measure the size of a patient's intervertebral foramen. Thesemethods may also form part of an overall method of treatment of a spine.One or more of the dimensions of a subject's intervertebral space,lateral recess or central canal may be determined prior to adecompressing the spine, during the decompression of the spine, and/orafter the decompression of the spine.

Described herein are methods of measuring the size of a compliant regionadjacent to a patient's nerve root including the steps of: advancing aguidewire from a first position outside of the patient's body, throughan intervertebral foramen, and out of the patient's body at a secondposition; coupling the distal end of a measurement device to theguidewire; advancing the measurement device at least partway into theintervertebral foramen, lateral recess and/or central canal, using theguidewire; and estimating a size of the region adjacent to the patient'snerve root, based on the advancement of the measurement device into theforamen. The step of advancing the measurement device may includepulling it into the intervertebral foramen, lateral recess and/orcentral canal behind the guidewire. In other variations, the measurementdevice may be advanced by sliding it over the guidewire (e.g., pushingfrom behind, and/or pulling distally from a second wire or connector).

In general, the guidewire may be passed through the patient by firstusing a cannulated probe to guide the guidewire from a first locationoutside of a subject's back (e.g., dorsal/posterior to the patient'sintervertebral foramen), through the body, and through theintervertebral foramen. In some variations the guidewire may include asharp (or tissue-penetrating) distal end, so that after passing throughthe intervertebral foramen, the guidewire may be passed through thetissue and back out of the subject from a second locationdorsal/posterior to the intervertebral foramen.

Any one of the measurement devices described herein may be used as partof this method. For example, in some variations multiple measurementdevices are provided, each of a different diameter, and whereinestimating the size of the foramen comprises determining a largest ofthe devices that can pass into the foramen.

In some variations expandable measurement devices may be used. Forexample, the method may include the step of expanding an expandableregion of the measurement device. For example, an expandable region maybe expanded by passing fluid into the expandable region of themeasurement device to expand the region. The size of the measurementdevice (and therefore a size or dimension of the compliant regionadjacent to the nerve root, e.g., the intervertebral foramen) may beestimated based on the amount of fluid that can be passed into theexpandable portion.

The step of estimating the size of the compliant region adjacent to thenerve root (e.g., foramen) may include any reasonable estimation of thedimension of the region. For example, the step of estimating the sizemay refer to estimation of the diameter, minimum and/or maximumdiameter, volume, cross-sectional area. The compliant region adjacent tothe nerve root may be the intervertebral foramen, the lateral recessand/or the central canal. For example, the step of estimating the sizeof the compliant region adjacent to the nerve root may includeestimating the size of the diameter, volume, or cross-sectional area ofthe intervertebral foramen adjacent or around the nerve root.

Any of the methods described herein may include the step of applyingneural stimulation from the measurement device and monitoring for EMGsignals. Neural stimulation may be applied from one or more discreteregions, sections, sub-regions or subsections along the measurementdevice. In some variations the neural stimulation is applied by use ofone or more “tight bipole pairs.” Thus, current may be applied to one ormore bipole pairs on the surface of the device that are only slightlyseparated, or separated by a small distance (e.g., less than a fewmillimeters, less than 1 mm, etc). The exposed surfaces of the anode andcathode forming the bipole are typically also small (e.g., less than 2mm2, less than 1 mm2, etc.). In some variations, neural stimulation isapplied by the measurement device to determine which portion of themeasurement device a nerve within the intervertebral foramen isnear-contacting or contacting; the regions may be independentlyactivated and correlated to a known diameter. In this way, the diameterof the intervertebral foramen nearest a nerve (e.g., the nerve root) maybe determined. In some variations, neural stimulation may be used tohelp properly advance and position the measurement device.

In some variations, the measurement device includes one or more moldableregion, and the method of measuring may include the step of molding amoldable region of the measurement device within the intervertebralforamen and withdrawing the molded region. For example, the moldableregion may be advanced distally (by pulling on the distal end using theguidewire), allowing the moldable region to conform to theintervertebral foramen. The moldable measuring device may be advanceddistally with a light force (e.g., less than 1 lb of force), so that thematerial may mold to the intervertebral foramen, and then the device maybe withdrawn proximally and examined to determine a measure of theintervertebral foramen.

Any of the methods described herein may be used percutaneously. Forexample the guidewire and/or the measurement device may be advancedpercutaneously.

Also described herein are methods of measuring the size of a compliantregion adjacent to a patient's nerve root as part of a spinaldecompression procedure. In some variations, this method may include thesteps of advancing a guidewire from a first position outside of thepatient's body, through an intervertebral foramen, and out of thepatient's body at a second position, pulling the measurement device atleast partially into the intervertebral foramen (wherein the measurementdevice is coupled to the proximal portion of the guidewire), expanding aportion of the measurement device, and estimating a size of thecompliant region adjacent to the nerve root, based on the expansion ofthe measurement device.

Any of the methods described herein may also include the step ofcoupling the measuring device to the guidewire. For example, proximalend of the guidewire may be coupled to the distal end of the measuringdevice.

The step of expanding the portion of the measurement device may includepassing a fluid into the portion. For example, fluid may be passed intoan expandable balloon of the measurement device. Fluid may be passedinto the portion until it reaches a predetermined pressure. In somevariations, the fluid is radiopaque. Thus, the method may also includetaking a radiographic image of the expanded portion using a radiographicdevice.

In some variations the method may also include the step of activating atransducer to estimate the size of the expanded portion. Any appropriatetransducer may be used. The transducer may be included as part of themeasurement device. For example, the transducer may be an optical/visualtransducer (e.g., camera, CCD, etc.), a sound transducer (e.g.,ultrasound, etc.), or the like. In some variations the method includesthe step of rotating the transducer within an inflatable element toestimate the size of the intervertebral foramen. For example, the sizemay be estimated by measuring the expansion of the balloon (e.g.,distance to the walls) using the intervertebral foramen.

In some variations, the step of expanding the portion of the measurementdevice comprises passing an expansion member into an expandable portionof the device. For example, the measurement device may include aplurality of expansion members configured as wires, rods, or the like,that may be advanced into an expandable element (e.g., bag, balloon,etc.) to expand it within the intervertebral foramen, central canaland/or lateral recess. The number of expansion members used before thedevice cannot be expanded any further may help provide an indication ofthe size of the device.

Also described herein are methods for measuring the size of a compliantregion adjacent to a patient's nerve root that include electricalstimulation that may help identify the proximity of the measurementdevice to the nerve root as the measurement device is advanced. Thiselectrical stimulation may prevent damaging (e.g., crushing or applyingundesirable pressure) to the nerve root. For example, the method mayinclude the steps of: advancing a guidewire from a first positionoutside of the patient's body, through an intervertebral foramen, andout of the patient's body at a second position, applying an electricalcurrent between a pair of tight bipolar electrodes on a measurementdevice, advancing the measurement device until the patient's nerve rootis stimulated by the applied electrical current, wherein the measurementdevice is coupled to the guidewire, and estimating a size of the regionadjacent to the nerve root, based on the advancement of the measurementdevice.

Also described herein are measurement devices for measuring anintervertebral foramen as part of a spinal decompression procedure. Ingeneral, a measurement device may include a proximal end configured tobe gripped (which may include a handle), a guidewire coupling region atthe distal end (the guidewire coupling region configured to mate withthe proximal end of a guidewire), and a flexible sound region near thedistal end, wherein the sound region is configured to be pulled at leastpartially through the intervertebral foramen and provide indication ofthe dimension of the intervertebral foramen.

Any appropriate sound region may be used, as mentioned above. Forexample, the sound region of the measurement device may comprise aplurality of calibrated sounds of increasing dimension extendingproximally from the distal region. In some variations, the sound regionincludes neural stimulation. For example, the sound region may include aplurality of bipolar pairs configured to produce a bipole filedsufficient to activate an adjacent nerve.

In some variations, the sound region may comprise an expandable regionconfigured to be expanded (e.g., within the intervertebral foramen). Theexpandable region may be an inflatable balloon. In some variations, themeasurement device further comprises an expansion member configured tobe advanced distally and expand the expandable region. In somevariations, the measurement device includes a moldable region.

Also described herein are systems for measuring the size of a compliantregion adjacent to a patient's nerve root as part of a spinaldecompression procedure. The system may include a guidewire having adistal end and a proximal end, and configured to pass from a firstposition outside of a patient's body, through an intervertebral foramen,and out of the patient's body at a second position, and a measurementdevice including a flexible sound region near the distal end, and aguidewire coupling region at the distal end, the guidewire couplingregion configured to mate with the proximal end of the guidewire;wherein the sound region is configured to be advanced at least partiallythrough the intervertebral foramen and provide indication of thedimension of the intervertebral foramen.

As mentioned above, any appropriate sound region may be included as partof the measurement device in the system. For example, the sound regionof the measurement device may comprise a plurality of calibrated soundsof increasing dimension extending proximally from the distal region. Insome variations, the sound region comprises a plurality of bipolar pairsconfigured to produce a bipole filed sufficient to activate an adjacentnerve. In some variations, the sound region comprises an expandableregion configured to be expanded within the intervertebral foramen. Insome variations the expandable region is an inflatable balloon. Themeasurement device may include a moldable region; in some variations thesound region is a moldable region. The measurement device may alsoinclude an expansion member configured to be advanced distally andexpand the expandable region.

Any appropriate guidewire may be used. For example, the guidewire mayinclude a shaped proximal end for coupling with the first and secondflexible wires. The guidewire may also have a relatively sharp (e.g.,tissue penetrating) distal end.

Also described herein are systems for measuring an intervertebralforamen as part of a spinal decompression procedure. The systems mayinclude a guidewire having a distal end and a proximal end, andconfigured to pass from a first position outside of a patient's body,through an intervertebral foramen, and out of the patient's body at asecond position, a first measuring device and a second measuring device.The first measuring device may include a first flexible wire having atip coupler for coupling the wire the proximal end of the guidewire forpulling the wire into the intervertebral foramen and a first soundfixedly coupled with the first wire and having a first diameter. Thesecond measuring device may include: a second flexible wire having a tipcoupler for coupling the wire with the proximal end of the guidewire forpulling the wire into the intervertebral foramen, and a second soundfixedly coupled with the second wire and having a second diameter.

Also described herein are devices for measuring an intervertebralforamen as part of a spinal decompression procedure including: aflexible wire passable through an intervertebral foramen having a distaltip coupler for coupling with a guidewire, and a distal tapered soundregion fixedly coupled with the flexible wire for passing into theintervertebral foramen, wherein the tapered sound comprises a moldablematerial configured to hold the shape of at least a portion of theintervertebral foramen when withdrawn from the intervertebral foramen.

Also described herein are devices for measuring an intervertebralforamen as part of a spinal decompression procedure including: aflexible catheter passable into an intervertebral foramen and havingproximal and distal ends, an inflatable balloon disposed along thecatheter at or near its distal end, and a coupler disposed along thecatheter at or near its distal end for coupling the catheter with aguidewire. The device may also include a transducer suspended on a wirepassing through the inflatable balloon for measuring the innerdimensions of the balloon. As mentioned above, the transducer may be anoptical transducer (camera). In some variations, the device alsoincludes a second balloon coupled with the catheter at or near itsproximal end, wherein the second balloon inflates or deflates inresponse to the opposite reaction (inflation/deflation) of theinflatable balloon, when the latter is inflated in the intervertebralforamen.

Also described are devices for measuring an intervertebral foramen aspart of a spinal decompression procedure, in which the devices include aflexible catheter passable through an intervertebral foramen and havingproximal and distal portions, and an expandable braided portion betweenthe proximal and distal portions. The device is configured so thatpulling on the proximal and distal portions causes the expandableportion to assume an unexpanded configuration and pushing the proximaland distal portions toward one another causes the expandable portion toexpand. Further, the braided portion is radio opaque.

Also described herein are devices for percutaneously measuring anintervertebral foramen as part of a spinal decompression procedure, thedevices having: a flexible catheter configured to pass through anintervertebral foramen, the catheter having proximal and distalportions, and an expansion region, a plurality of long, flexibleexpansion members configured to pass into the expansion region, whereinthe expansion region is configured to expand as the expansion membersare passed therein, and a guidewire coupling region configured to couplethe catheter with a guidewire that can advance the catheter into theforamen.

In some variations, the guidewire coupling region comprises a guidewirecoupler at or near the distal end of the catheter for allowing thecatheter to be pulled into the foramen behind the guidewire. In othervariations, the guidewire coupling region comprises a guidewire lumenfor allowing the catheter to be passed into the foramen over aguidewire.

Any of the methods, systems and devices described above for use in theintervertebral foramen may also be used (and/or adapted for use) todetermine the size of a compliant region adjacent to a nerve root withinother regions other than just the intervertebral foramen. For example,these systems, devices and methods may be used to determine the size ordimensions of the lateral recess or central canal (particularly theportion of these structures near the nerve root).

Described herein are systems for accessing a spine and particularly theepidural region of the spine, devices for accessing the spine, andmethods of using these systems and devices to access the spine orregions of the spine. In particular, cannulas that may be anchored tothe ligamentum flavum or the periosteum are described. Other accessmethods and associated tools for achieving safe and reliable spinal(e.g., epidural) access are also described. In particular, ligamentumflavum access tools are described. These tools may be used with (orwithout) an anchoring cannula to penetrate the ligamentum flavum andprovide access to the epidural space without risk of injury to otherstructures within the epidural space. The devices, methods and systemsdescribed herein are particularly useful in minimally invasive surgical(MIS) uses. For example, these tools and methods may be useful inpercutaneous procedures. Any of these tools may also be used in an opensurgical setting as well. The devices, methods and systems describedherein may be used for performing spinal decompressions and other spinalprocedures.

For example, anchoring cannula, systems including them, and proceduresusing them are described. Although a cannula may be anchored either tothe patient or to a structure outside of the patient, for many of themethods described herein it may be particularly helpful to provide acannula that is distally anchorable to a spinal structure such as theligamentum flavum or the periosteum of the spine. For example, describedherein are methods for accessing a spine of a patient may involveadvancing a cannula into the patient to contact a distal end of thecannula with spinal tissue including at least one of ligamentum flavumor vertebral periosteum, removeably attaching the distal end of thecannula to at least one of the ligamentum flavum or the periosteumand/or bone, advancing a curved, at least partially flexible, cannulatedguide member through the cannula and through at least one of theligamentum flavum or vertebral periosteum to position a distal portionof the guide member in the epidural space of the spine, such that whenthe distal portion exits the cannula it assumes a preformed curvedshape, and advancing the distal portion of the guide member at leastpartway into an intervertebral foramen of the spine.

In some embodiments, the cannula may be advanced along with an epiduralneedle, with the cannula disposed over the needle as a sheath, and themethod further involve removing the needle before advancing the guidemember through the cannula. For example, in one embodiment, removing theneedle may involve ejecting the epidural needle proximally to remove atip of the needle from the epidural space and sliding the needleproximally out of the cannula. In an alternative embodiment, the cannulamay be advanced along with a blunt stylet, with the cannula disposedover the stylet as a sheath, and the method may further involve removingthe stylet before advancing the guide member through the cannula. Insome embodiments, rather than (or in addition to) a needle, a ligamentumflavum access tool may be used to penetrate the ligamentum flavum.Ligamentum flavum access tools are described in greater detail blow.

In some embodiments, attaching the distal end of the cannula to thetissue may involve turning the cannula about its longitudinal axis in afirst direction to couple one or more barbs disposed on its distal endwith the tissue. Such a method may further involve turning the cannulaabout its longitudinal axis in a second direction, opposite the firstdirection, to release the cannula from the tissue, after advancing theguide member into the intervertebral foramen. In some embodiments, themethod may also include, before advancing the guide member, advancing arigid, blunt, cannulated probe through the cannula to position a distalend of the probe in the epidural space, wherein the curved guide memberis advanced through the rigid probe.

In one embodiment, the method may also include advancing a guidewirethrough the guide member to pass through the intervertebral foramen andout the patient's skin, releasing the cannula from the spinal tissue,and removing the cannula and the guide member from the patient, leavingthe guidewire in place, extending into the patient, through theintervertebral foramen, and back out the patient. Such a method may alsooptionally include coupling a tissue removal device with the guidewire,advancing the tissue removal device at least partway into theintervertebral foramen, using the guidewire, and performing a tissueremoval procedure in the patient's spine.

In one embodiment, the method may further involve transmittingstimulating current to at least one electrode disposed on the curvedguide member to help determine a position of the guide member relativeto nerve tissue. For example, transmitting the current may involvetransmitting a first current to a first electrode disposed on an innercurvature surface of the guide member and transmitting a second currentto a second electrode disposed on an outer curvature surface of theguide member. In some embodiments, the method may further include,before the transmitting step, advancing a sheath comprising at least oneelectrode over the guide member into the epidural space of the spine. Inan alternative embodiment, the method may further involve, beforeadvancing the guide member, advancing at least one additional cannulaover the attached cannula, removeably attaching the additional cannulato the spinal tissue, removing the cannula from the tissue, andwithdrawing the cannula through the additional cannula.

Also described herein are methods for advancing a guidewire through anintervertebral foramen of a spine of a patient may involve advancing acannula into the patient to contact a distal end of the cannula withspinal tissue including at least one of ligamentum flavum or vertebralperiosteum, removeably attaching the distal end of the cannula to atleast one of the ligamentum flavum or the periosteum, advancing acurved, at least partially flexible, cannulated guide member through thecannula and through at least one of the ligamentum flavum or vertebralperiosteum to position a distal portion of the guide member in theepidural space of the spine, such that when the distal portion exits thecannula it assumes a preformed curved shape, advancing the distalportion of the guide member at least partway into an intervertebralforamen of the spine, advancing a guidewire through the guide member topass through the intervertebral foramen and out the patient's skin,releasing the cannula from the spinal tissue, and removing the cannulaand the guide member from the patient, leaving the guidewire in place,extending into the patient, through the intervertebral foramen, and backout the patient.

Also described herein are methods for advancing a guidewire through anepidural space of a spine of a patient may involve advancing a cannulainto the patient to contact a distal end of the cannula with spinaltissue including at least one of ligamentum flavum or vertebralperiosteum, removeably attaching the distal end of the cannula to atleast one of the ligamentum flavum or the periosteum, advancing acurved, at least partially flexible, cannulated guide member through thecannula and between first and second vertebrae to position a distalportion of the guide member in the epidural space of the spine, suchthat when the distal portion exits the cannula it assumes a preformedcurved shape, advancing the distal portion of the guide member at leastpartway between the second vertebra and a third vertebra of the spine,advancing a guidewire through the guide member to pass between thesecond and third vertebrae and out the patient's skin, releasing thecannula from the spinal tissue, and removing the cannula and the guidemember from the patient, leaving the guidewire in place, extendingbetween the first and second vertebrae, through the epidural space,between the second and third vertebrae, and back out the patient.

In another variation, a method for accessing an intervertebral foramenof a spine of a patient may suitably include removeably attaching adistal end of a first tissue locking cannula to spinal tissue includingat least one of ligamentum flavum or vertebral periosteum, passing atleast a second tissue locking cannula over the first cannula, removeablyattaching a distal end of the second cannula to the spinal tissue,removing the first cannula through the second cannula, advancing a probethrough the second cannula to position a distal portion of the probe inan epidural space of the patient's spine, advancing a curved, at leastpartially flexible, cannulated guide member through the probe, such thatwhen the distal portion exits the cannula it assumes a preformed curvedshape, and advancing the distal portion of the guide member at leastpartway into an intervertebral foramen of the spine.

In some embodiments, the method may further include advancing aguidewire through the guide member to pass through the intervertebralforamen and out the patient's skin, removing the probe from the patient,releasing the second cannula from the spinal tissue, and removing thecannula from the patient, leaving the guidewire in place, extending intothe patient, through the intervertebral foramen, and back out thepatient. In some embodiments, the method may further include, beforeadvancing the probe, passing at least a third tissue locking cannulaover the second cannula, removeably attaching a distal end of the thirdcannula to the spinal tissue; and removing the second cannula throughthe third cannula. In one embodiment, the method may further include,before advancing the probe, passing at least a fourth tissue lockingcannula over the third cannula, removeably attaching a distal end of thefourth cannula to the spinal tissue, and removing the third cannulathrough the fourth cannula.

Also described herein are systems for accessing a spine of a patient mayinclude at least one tissue locking cannula having multiple barbsdisposed at one end for removeably attaching to spinal tissue includingat least one of ligamentum flavum or vertebral periosteum, at least oneof a needle or a stylet slideably disposed in the cannula, and a curved,at least partially flexible, cannulated guide member slideably passablethrough the cannula and having a distal portion configured to changefrom a straight shape within the cannula to a curved shape upon exitingthe cannula, wherein the distal portion has a radius of curvatureconfigured to position the distal portion at least partway into anintervertebral foramen of the spine when advanced through the cannula.

Some embodiments may further include a rigid, cannulated probe slideablypassable through the cannula, wherein the curved guide member slide ablypasses through the probe. In some embodiments, the guide member may passthrough an end aperture of the probe. In alternative embodiments, theguide member may pass through a side aperture of the probe. In someembodiments, the system may further include at least one guidewire forpassing through the guide member. In some embodiments, the system mayfurther include a syringe for attaching to a proximal portion of theepidural needle. In some embodiments, the system may further include atissue removal device removeably couplable with the guidewire forpassing into the patient to remove spinal tissue.

In some embodiments, the tissue locking cannula may have an outerdiameter of between about 1 mm and about 20 mm. In one embodiment, thebarbs of the cannula may face in one direction and attach to tissue bypressing the barbs against the tissue and turning the cannula along itslongitudinal axis in a first direction. In one embodiment, the barbs mayrelease from tissue by turning the cannula along its longitudinal axisin a second direction opposite the first direction. In some embodiments,the guide member may include a rounded, atraumatic distal tip. In someembodiments, the at least one tissue locking cannula may includemultiple cannulas of different diameter, wherein a first cannula fitswithin a second cannula, and the second cannula fits within at least athird cannula.

Also described herein are systems for accessing a spine of a patient mayinclude: multiple tissue locking cannulas, each cannula having adifferent diameter such that larger cannulas slide over smallercannulas, and each cannula having multiple barbs disposed at one end forremoveably attaching to spinal tissue including at least one ofligamentum flavum or vertebral periosteum; a cannulated probe passablethrough at least a largest diameter cannula of the multiple cannulas;and a curved, at least partially flexible, cannulated guide member slideably passable through the probe and having a distal portion configuredto change from a straight shape within the probe to a curved shape uponexiting the probe, wherein the distal portion has a radius of curvatureconfigured to position the distal portion at least partway into anintervertebral foramen of the spine when advanced through the probe.

In some embodiments, the multiple cannulas may include between two andsix cannulas. In some embodiments, the probe may comprise a rigid probeincluding an approximately straight shaft portion and a curved distalportion, wherein the curve has an angle of curvature configured to allowthe distal portion to pass through at least a largest of the cannulas.

As mentioned above, the tissue locking (anchoring) spinal access systemsdescribed above, including the distally anchoring cannula, may be usedwith other access or spinal surgical tools. For example, any of thedevices and systems described above may be used with one or moreligamentum flavum access tools. In general, a ligamentum flavum accesssystem includes an outer cannula (which may be a distally anchoringcannula as described above), and an inner member that is controllablymovable relative to the outer member. In some variations, an additionalcannula is used, which fits within the outer cannula, and allows passageof the inner member. The system is typically configured to penetrate theligamentum flavum and cut or expand an opening therethrough, so that aprocedure may be performed on the spine. Any of these devices may alsoinclude one or more detectors for detecting when the system haspenetrated the ligamentum flavum and into the epidural space. Forexample, the system may include a hole or opening near the distal endfor detecting a loss of resistance once a portion of the system haspenetrated the ligamentum flavum.

For example, described herein is a ligamentum flavum access tool devicecomprising an outer hypotube having a distal cutting edge and an innermember having an atraumatic tissue contacting region that is movablewithin the outer hypotube, and extends from the outer hypotube, whereinthe inner member is configured to secure to a patient's ligamentumflavum. The device may also include a loss of resistance detectorconfigured to determine when the inner member is within the epiduralspace.

In some variations, the inner member includes a vacuum port configuredto provide a vacuum for securing the inner member to the ligamentumflavum. For example, the inner member may be an inner hypotube (e.g.,cannula) that includes an opening for applying a vacuum to hold theligamentum flavum securely. The outer hypotube (cannula) may have asharpened edge, so that by moving the outer hypotube relative to theinner hypotube, a hole in the ligamentum flavum may be cut. In any ofvariations one or both of the inner and outer members (e.g. an outerhypotube including a sharpened edge) may be rotatable relative to theinner member, which may help with cutting of the ligamentum flavum.

In some variations, the devices include at least one support elementextendable from the inner member when the inner member is within theepidural space. For example, the inner member may include one or morearms that extend from the distal region of the inner member after it haspassed into the epidural space, so that these arms or other extendableelements may support the ligamentum flavum so that it can be cut. Insome variations the support element(s) are arms made of Nitinol or othershape-memory or appropriately deformable material that may be extendedfrom the inner member (e.g., substantially perpendicular to the longaxis of the inner member.

In some variations, the atraumatic tissue contacting region of the innermember includes a distal head and a proximal neck that has a smallerdiameter than the distal head, wherein the ligamentum flavum may besecured around the proximal neck after the distal head has penetratedthe ligamentum flavum. For example, the inner member may have a“mushroom” shape that permits the tissue to be secured around thenarrower neck region after this head portion penetrates the ligamentumflavum.

Any of these devices (tools) may also include a threaded region on anouter surface of the device that is configured to mate with a cannula sothat the device may be controllably advanced within the cannula byrotation. Furthermore, the cannula may be an anchoring cannula thatincludes complimentary threads for advancing the tool by rotating.

In addition, the devices may also include an internal threaded region incommunication with the inner atraumatic tissue contacting member so thatit may be moved relative to the outer hypotube. For example, in somevariations the inner and outer members may be drawn together to cut theligamentum flavum.

Also described herein are ligamentum flavum access tool devicescomprising an elongate body, a distal tip member comprising anatraumatic tissue contacting region configured as a leading head, acutting surface that is located proximal to the distal tip member, and aloss of resistance detector, configured to determine when the distal tipmember is within the epidural space. The cutting surface may be locatedon a proximal side of the leading head of the distal tip member. Inother variations, the cutting surface is a cutting edge of a hypotube inwhich the distal tip member may axially move.

In some variations, the devices include at least one support elementextendable from the distal tip member when the distal tip member iswithin the epidural space. The distal tip member may be axially movablerelative to the cutting surface.

As mentioned above, the device may also include a threaded region on anouter surface of the device that is configured to mate with a cannula sothat the device may be controllably advanced within the cannula byrotation, and/or an internal threaded region in communication with thedistal tip member so that the distal tip member may be moved relative tothe cutting surface.

Also described herein are ligamentum flavum access tool devicescomprising a proximal hypotube having an expandable distal end, and adistal tip member comprising an atraumatic leading that is axiallymovable relative to the proximal hypotube, and a loss of resistancedetector, configured to determine when the proximal hypotube is withinthe epidural space. The expandable distal end of the proximal hypotubemay include a plurality of axial slits.

In some variations, the proximal hypotube is configured to be anchoredin position within the ligamentum flavum.

Also described herein are systems for accessing a patient's spine. Forexample, a system may include a cannula configured to be anchored incontact with the ligamentum flavum, a ligamentum flavum access toolconfigured to be controllably advanced within the cannula, and a curvedcannulated guide member passable through the cannula and having a distalportion configured to change from a straight shape within the cannula toa curved shape upon exiting the cannula, wherein the distal portion ofthe guide member has a radius of curvature configured to position thedistal portion at least partway into an intervertebral foramen of thespine when advanced through the cannula. The ligamentum flavum accesstool may include any of those described herein. For example, theligamentum flavum access tool may include a proximal hypotube having acutting edge, and a distal atraumatic tissue contacting region that ismovable relative to the proximal hypotube. The ligamentum flavum accesstool may include a threaded region that mates with a threaded portion ofthe cannula so that the ligamentum flavum access tool may becontrollably advanced by rotation.

In some variations, the ligamentum flavum access tool further comprisesa load of resistance detector.

The distal atraumatic tissue contacting region of the ligamentum flavumaccess tool may include a leading head having an atraumatic surface. Insome variations, the distal atraumatic tissue contacting region of theligamentum flavum access tool comprises a vacuum port configured tosecure the ligamentum flavum to the distal atraumatic tissue contactingregion.

In some variations, the distal atraumatic tissue contacting region ofthe ligamentum flavum access tool may include at least one supportelement extendable from the atraumatic tissue contacting region when theatraumatic tissue contacting region is within the epidural space.

Any of the systems for accessing the spine described herein may includeany of the elements described above for performing a spinal procedure,particularly a spinal decompression procedure. For example, the systemmay also include a cannulated probe configured to allow the cannulatedguide member to pass and further configured to pass through the cannula,and/or at least one guidewire configured to pass through the cannulatedguide member.

The cannula included as part of the system may be a tissue lockingcannula as described above, such as a cannula having a plurality ofbarbs disposed at or near the distal end for removeably anchoring thelocking cannula in communication with the ligamentum flavum.

Also described herein are systems for accessing a patient's spineincluding a cannula configured to be anchored in contact with theligamentum flavum, a ligamentum flavum access tool configured to becontrollably advanced within the cannula, and a curved cannulated guidemember passable through the cannula and having a distal portionconfigured to change from a straight shape within the cannula to acurved shape upon exiting the cannula, wherein the distal portion of theguide member has a radius of curvature configured to position the distalportion at least partway into an intervertebral foramen of the spinewhen advanced through the cannula. The ligamentum flavum access tool mayinclude a proximal hypotube having an expandable distal end, and adistal tip member comprising an atraumatic leading that is movablerelative to the proximal hypotube.

The distal tip member may be further configured to expand the expandabledistal end of the proximal hypotube when the distal tip member is passedthrough the proximal hypotube.

Also described herein are systems for accessing a patient's spine, thesystem comprising a cannula configured to be anchored in contact withthe ligamentum flavum, a ligamentum flavum access tool configured to becontrollably advanced within the cannula, and a curved cannulated guidemember passable through the cannula and having a distal portionconfigured to change from a straight shape within the cannula to acurved shape upon exiting the cannula, wherein the distal portion of theguide member has a radius of curvature configured to position the distalportion at least partway into an intervertebral foramen of the spinewhen advanced through the cannula. The ligamentum flavum access tool maycomprise a proximal cutting surface, a distal tip member comprising anatraumatic tissue contacting region configured as a leading head, and aloss of resistance detector.

Methods of accessing the spine using any of the elements describedabove, such as the spinal access tool device, and systems includingthem, may be performed either percutaneously or in an open procedure. Inparticular any of these devices, tools or systems may be used as part ofa procedure for accessing the epidural space of the spine.

For example, described herein are methods of accessing the spine of apatient comprising the steps of: anchoring the distal end of a cannulain contract with a patient's ligamentum flavum; advancing a ligamentumflavum access tool within the cannula in a controlled manner;penetrating the ligamentum flavum with the ligamentum flavum access toolto access the epidural space; and forming an opening in the ligamentumflavum with the ligamentum flavum access tool. The ligamentum flavumaccess tool may be any of those described above.

In one variation, a method of accessing the spine of a patient includesthe steps of: anchoring the distal end of a cannula in contract with thepatient's ligamentum flavum; advancing a ligamentum flavum access tooldistally within the cannula in a controlled manner (wherein theligamentum flavum access tool comprises an outer hypotube having adistal cutting edge, and an inner member comprising an atraumatic tissuecontacting region that is movable within the outer hypotube, and extendsdistally from the outer hypotube); securing the ligamentum flavum to theatraumatic tissue contacting region of the ligamentum flavum accesstool; and cutting an opening in the ligamentum flavum with the cuttingedge of the proximal hypotube.

The step of securing the ligamentum flavum to the atraumatic tissuecontacting region of the ligamentum flavum access tool may comprisesapplying a vacuum to hold the ligamentum flavum to the atraumatic tissuecontacting region. In some variations, the step of securing theligamentum flavum to the atraumatic tissue contacting region of theligamentum flavum access tool comprises deploying one or more supportelements from the atraumatic tissue contacting region when atraumatictissue contacting region is within the epidural space. In yet othervariations, the step of securing the ligamentum flavum to the atraumatictissue contacting region of the ligamentum flavum access tool comprisespenetrating the ligamentum flavum with the atraumatic tissue contactingregion until the atraumatic tissue contacting region is within theepidural space as determined by the loss of resistance detector.

The step of cutting an opening in the ligamentum flavum may comprisemoving the atraumatic tissue contacting region secured to the ligamentumflavum proximally so that the ligamentum flavum is cut by the cuttingedge of the outer hypotube. In some variations, the step of cutting anopening in the ligamentum flavum comprises moving the cutting edge ofthe outer hypotube distally relative to the atraumatic tissue contactingregion secured to the ligamentum flavum.

Any of these methods may also include the step of removing theligamentum flavum access tool from the cannula.

The step of anchoring the distal end of the cannula may includeremoveably attaching the distal end of the cannula to the ligamentumflavum, including securing a distally anchoring cannula as describedabove. Alternatively (or in addition), the step of anchoring the distalend of the cannula may include anchoring the cannula to a surgicalaccess platform.

The step of advancing the ligamentum flavum access tool may includerotating the tool relative to the cannula to advance the tool along athreaded region.

Also described herein are methods of accessing the spine of a patientcomprising the steps of: anchoring the distal end of a cannula incontract with the ligamentum flavum; advancing a ligamentum flavumaccess tool distally within the cannula in a controlled manner (whereinthe ligamentum flavum access tool comprises a proximal cutting surface,a distal tip member comprising an atraumatic tissue contacting regionconfigured as a leading head, and a loss of resistance detector);penetrating the ligamentum flavum with the atraumatic leading head ofthe tip region until the atraumatic leading head accesses the epiduralspace as determined by the loss of resistance detector; cutting theligamentum flavum with the proximal cutting surface; and removing theligamentum flavum access tool from the cannula.

The step of cutting the ligamentum flavum with the proximal cuttingsurface may comprise compressing the ligamentum flavum between thedistal tip member and the proximal cutting surface. In some variations,the step of cutting the ligamentum flavum with the proximal cuttingsurface comprises retracting the distal tip member so that the proximalcutting surface can engage the ligamentum flavum.

Any of the methods described herein may also include the step ofdeploying one or more support elements from the distal tip member whenthe distal tip member is within the epidural space.

Also described herein are methods of accessing the spine of a patientcomprising: anchoring the distal end of a cannula in contract with theligamentum flavum; advancing a ligamentum flavum access tool distallywithin the cannula in a controlled manner (wherein the ligamentum flavumaccess tool comprises a proximal hypotube having an expandable distalend, and a distal tip member comprising an atraumatic leading head);penetrating the ligamentum flavum with the atraumatic leading head ofthe tip region until the expandable distal end of the hypotube spans theligamentum flavum; and dilating the expandable distal end of thehypotube to expand an opening in the ligamentum flavum.

The step of dilating the expandable distal end of the hypotube mayinclude withdrawing the distal tip member proximally through thehypotube to expand the distal end of the hypotube.

The method may also include a step of removing the atraumatic leadinghead from the hypotube to allow access to the patient's epidural spacethrough the cannula.

The step of penetrating the ligamentum flavum comprises determining whenthe distal end of the hypotube has entered the epidural space. Forexample, a loss of resistance detector may be used, as described.

Described herein are medical devices for insertion into tissue thatinclude a tight bipole network configured to detect nerve tissueimmediately adjacent to the tissue manipulation region of the device.These medical devices may be referred to as “smart tools” because theycan sense, and in some variations react to, the presence of nervetissue. For example, described herein are rongeur devices including atight bipole network. The tight bipole network is part of the tissuereceiving portion of the rongeur, and is arranged so that it emits abroadcast field (e.g., current) that will stimulate a nerve that ispresent in the tissue receiving portion of the rongeur. The device isconfigured so that the broadcast field will not extend substantiallybeyond the tissue receiving portion, therefore providing specificity.The tight bipole network may also be arranged so it extends along thelength of the tissue manipulation region of the medical device.

For example, described herein are tissue manipulation devices that candetect the presence of a nerve in a tissue to be manipulated by thedevice. These devices may include: a tissue receiving portion includinga first tissue receiving surface and a second tissue receiving surface,wherein the first tissue receiving surface is configured to moverelative to the second tissue receiving surface to engage tissue withinthe tissue receiving portion; and a tight bipole network incommunication with the tissue receiving portion, wherein the tightbipole network is configured to emit a broadcast field that is limitedto the tissue receiving portion and sufficient to stimulate a nervewithin the tissue receiving portion.

The tissue manipulation device may be any device that includes a tissuereceiving portion which can include a tight bipole network. For example,a tissue manipulation device may include a rongeur, a scissor, a clam, atweezers, or the like. Rongeurs are of particular interest and aredescribed in greater detail below, although much of this description maybe applied to other tissue manipulation devices as well. A tissuemanipulation device may be a tissue modification device. In general, atissue manipulation device may include an elongate device (including aprobe) that can be inserted into a patient, either in an open procedureor a percutaneous procedure. Thus, it may include a handle and/or anelongate body.

The tissue receiving portion of the tissue manipulation device may be acavity or opening on the device into which tissue may fit or be placed.The tissue receiving portion may be static (e.g., a fixed size and/orshape), or it may be dynamic. For example, the tissue receiving portionmay be made smaller to clamp or cut tissue. The tissue receiving portionmay be located on the distal end, or near the distal end, of a device.In some variations, the tissue receiving portion opens from a side ofthe device that is proximal to the distal end of the device. The tissuereceiving portion may be configured as a jaw.

As mentioned above, the tissue manipulation device may include a handleproximal to the tissue receiving portion. The handle may include acontrol for moving the first tissue receiving surface and/or the secondtissue receiving surface. Any appropriate control may be used, e.g.,knob, lever, dial, slider, etc. The tissue manipulation device may alsoinclude an elongate body extending proximally to the tissue receivingportion. This elongate body may be rigid, flexible, steerable, orcapable of being made rigid or flexible along all or a portion of itslength (e.g., by tensioning/un-tensioning an internal member, or byadding or removing a stiffening member, by inflating or deflating astiffening bladder or the like).

The second tissue receiving surface may be movable or not movable. Forexample, the second tissue receiving surface may be formed from theelongate body of the device.

Tight bipole networks are described in greater detail below. In general,a tight bipole network includes at least one bipole pair of electrodesthat are sufficiently close so that the current flowing between themforms a broadcast field that is very limited, allowing the tight bipolenetwork to stimulate (and therefore allow detection of) nerves that arein the immediate region of the bipole network (e.g., adjacent to orcontacting). A tight bipole network may include a plurality of anodesand cathodes that are arranged within the tissue receiving portion.Tight bipole network may include a plurality of anodes and cathode pairsthat are arranged to form an effectively continuous bipole field withinthe tissue receiving portion. For example, a line of anodes and cathodes(which may be alternating) may be arranged down the length of the tissuereceiving portion. In some variations, a line of cathodes and a line ofanodes may be formed by creating openings (vias) to a wire or length ofcathode extending proximally and a wire or length of anode extendingproximally.

As mentioned, the tissue manipulation device may be configured as arongeur and the first tissue receiving surface may be configured to moverelative to the second tissue receiving surface to cut tissue within thetissue receiving portion. Other examples of rongeurs are describedherein.

For example, also described herein are rongeur devices for cuttingtissue that can detect the presence of a nerve in the tissue to be cut.A rongeur device may comprise: a jaw having a tissue receiving portion,the tissue receiving portion including a first tissue receiving surfaceand a second tissue receiving surface, wherein the first tissuereceiving surface is configured to move towards the second tissuereceiving surface to cut tissue within the tissue receiving portion; anda tight bipole network on the jaw configured to emit a broadcast fieldthat is limited to the tissue receiving portion and sufficient tostimulate a nerve within the tissue receiving portion.

As with any of the tissue manipulation devices described, a rongeurdevice may include a handle, and/or an elongate body, wherein the jaw islocated at the distal region of the elongate body. In some variations,the second tissue receiving surface is not movable. As described above,the tight bipole network comprises a bipole pair, and in somevariations, the tight bipole network comprises a plurality of anodes andcathodes arranged within the tissue receiving portion. The tight bipolenetwork may comprise a plurality of anodes and cathodes configured toform an effectively continuous bipole field within the tissue receivingportion.

Also described herein are rongeur devices for cutting tissue that candetect the presence of a nerve in the tissue to be cut, the rongeurdevice comprising: a handle; an elongate body extending distally fromthe handle along a longitudinal axis; a tissue receiving portion nearthe distal end of the elongate body, the tissue receiving portionincluding a first tissue receiving surface and a second tissue receivingsurface, wherein the first tissue receiving surface is configured tomove longitudinally towards the second tissue receiving surface to cuttissue within the tissue receiving portion; and a tight bipole networkin communication with the tissue receiving portion wherein the tightbipole network is configured to emit a broadcast field that is limitedto the tissue receiving portion and sufficient to stimulate a nervewithin the tissue receiving portion.

Methods of using these tissue manipulation devices are also described.In general, the method of using a tissue manipulation device includesplacing a tissue within the tissue receiving portion of the tissuemanipulation device, energizing a tight bipole network to emit abroadcast field that is limited to the tissue receiving portion, anddetermining if a nerve or portion of a nerve is within the tissuereceiving portion.

For example, described herein are methods of cutting tissue using arongeur device capable of determining if a nerve is present in thetissue to be cut. These methods typically include the steps of placingtissue within a tissue receiving portion of the rongeur device,energizing a tight bipole network to emit a broadcast field that issubstantially limited to the tissue receiving portion, determining if anerve or a portion of a nerve is present in the tissue receiving portionof the rongeur device, and cutting the tissue within the tissuereceiving portion of the rongeur device.

The step of energizing the tight bipole network may include applyingenergy to a plurality of bipole pairs in communication with the tissuereceiving portion of the rongeur device. For example, energizing thetight bipole network comprises emitting an effectively continuous bipolefield within the tissue receiving portion of the rongeur device.

The step of determining if a nerve or portion of a nerve is present maybe performed in any appropriate way. Generally, this may includeobserving either the electrical activity of the nerve directly (e.g., bymonitoring downstream electrical activity) or by monitoring the activityof the target of the nerve. In some variations, this means observingmuscle activity, when the nerve(s) stimulated by the tight bipolenetwork enervate a muscle or muscles. For example, activation of a nervemay be observed by detecting EMG (electromyogram) activity, or byobserving/monitoring muscle twitch. This observation may be correlatedwith the timing of stimulation of the tight bipolar pair.

The step of cutting may include actuating the handle of the rongeurdevice to move a first tissue receiving surface of the tissue receivingportion of the rongeur device towards a second tissue receiving surface.In general, the tissue may be cut if a nerve or portion of a nerve isnot present in the tissue receiving portion of the rongeur device.

In general, an accelerometer-based device or system may be used todetermine stimulation of a nerve to determine proximity of the nerve toa neurostimulation electrode (including a tight bipole network) on atool that is inserted into a patient. For example, an accelerometer maybe placed on the patient to detect muscle twitch due to stimulation froma neurostimulation electrode. The signal from the accelerometer may befiltered (e.g., to remove low-frequency movement artifact), and may becoordinated with the stimulation by the neurostimulation electrode(e.g., time-synchronized). The use of an accelerometer as describedherein may be advantageous over most currently used EMG type systems.For example, an accelerometer-based system may eliminate the need for atrained EMG technician.

The accelerometer may be disposable or re-usable. For example, in adisposable configuration the accelerometer may be secured to the patientand connected to a feedback controller that receives signals from theaccelerometer and/or the stimulator controlling the neurostimulationelectrode. The feedback controller may analyze the signal and provide anoutput from the accelerometer. Any appropriate output may be used (e.g.,visual, audible, etc.). For example, a display may be used to indicatestimulation of a nerve by the neurostimulation electrode.

In some variations, the output may be feed back into the control of thetool that is inserted into the body. For example, when the tool is acutting device (e.g., a rongeur, etc.), feedback from the feedbackcontroller indicating the presence of a nerve may prevent the devicefrom cutting. In some variations, when the tool is a probe, catheter, orthe like, the feedback may be used to steer the tool. Any appropriatetool may be used, including tissue manipulation devices as describedabove, but also including other insertable tools (and not limited tojust tissue manipulation tools like rongeurs). For example a tool may bean implant, such as a screw.

Thus, described herein are systems for determining if a nerve is nearbyan insertable tool. Such systems may include: an insertable tool havinga first surface comprising a neurostimulation electrode configured todetect proximity to a nerve; an accelerometer to detect muscle movementupon stimulation of a nerve by the neurostimulation electrode; and afeedback controller configured to receive input from the accelerometerand determine activation of a nerve by the neurostimulation electrode,wherein the feedback controller is further configured to providefeedback to tool to control operation of the tool. As mentioned above,example of tools may include any tool for insertion into the body thatmay be used with a neurostimulation electrode, including (but notlimited to): a probe, a pedicle screw, and an implant.

The system may also include a power source for applying power to theneurostimulation electrode. The power source may be (or may connect to)a controller configured to control the neurostimulation electrode. Thissystem may be used with any appropriate neurostimulation electrode,including a monopolar neurostimulation electrode, a bipole pair, aplurality of monopolar electrodes, a plurality of bipole pairs, and atight bipole network configured to emit an effectively continuous bipolefield, as described herein.

In some variations, the accelerometer is a multiple axis accelerometer.As mentioned, the accelerometer may be a durable/reusable accelerometer,or it may be a disposable accelerometer.

The feedback controller may be coupled to, or may include it own,output. As mentioned above, the output may be a visual output (monitor,light, LED, etc.), or an audible output (speaker, etc.), or any otherappropriate output. In some variations, the feedback controller isconfigured to provide feedback to the tool indicating detection of anerve.

Also described herein are systems for determining if a nerve is nearbyan insertable tool. These systems may include: an insertable tool havinga first surface comprising a tight bipole network configured to emit aneffectively continuous bipole field; an accelerometer to detect musclemovement upon stimulation of a nerve by the tight bipole network; and afeedback controller configured to receive input from the accelerometerand determine activation of a nerve by the neurostimulation electrode.

Methods of using accelerometer-based systems for determining if a nerveis nearby a tool are also described. For example, a method ofcontrolling a tool insertable into a human body may include the stepsof: securing an accelerometer to a patient's body; inserting a tool intothe patient's body; applying energy to a neurostimulation electrode onthe surface of the tool; and monitoring the accelerometer to determinemuscle twitch resulting from the application of energy to theneurostimulation electrode. The method may also include the step ofcomprising providing feedback to the tool based on the output of theaccelerometer.

The step of monitoring the accelerometer may also include filtering theoutput of the accelerometer to remove artifact. Any appropriatefiltering may be used, including spectral (power/frequency) filtering,band pass filter, high pass filtering, low pass filtering, and the like.In some variations the accelerometer is ‘tuned’ (e.g., sensate to) aparticular range of motion that corresponds to muscle twitch due tonerve stimulation. The step of monitoring the accelerometer may alsoinclude the step of synchronizing the monitoring of the accelerometerwith the application of energy to the neurostimulation electrode.

The step of applying energy to a neurostimulation electrode may alsoinclude applying energy to a tight bipole network to emit an effectivelycontinuous bipole field. Accelerometer-based detection systems may beparticularly useful for determining when a nerve is adjacent or incontact with a tool or device including the tight bipole pair networksdescribed.

An accelerometer may be applied to the patient in any appropriatemanner, including applying to the surface of the patient's skin. Forexample, the accelerometer may be adhesively applied, or may be appliedusing a wrap or strap that secures it to the patient. In some variationsa garment is worn that includes one or more integrated accelerometers.The step of applying an accelerometer to the surface of a patient's bodymay include applying a plurality of accelerometers to the surface of thepatient's body. In some variations the accelerometer may be implantedinto the patient.

Also described herein are methods of controlling a tool insertable intoa human body using the accelerometer-based systems described. Forexample, a method may include the steps of: securing an accelerometer toa patient's body; inserting a tool into the patient's body; applyingenergy to a tight bipole network to emit an effectively continuousbipole field on the surface of the tool; and monitoring theaccelerometer to determine muscle twitch resulting from the applicationof energy to the tight bipole network. As mentioned above, the methodalso includes the step of providing feedback to the tool based on theoutput of the accelerometer.

In general, described herein are methods for precisely placing and/ormanipulating devices within the body by first positioning a guidewirethrough the body from a first location, around a curved pathway, and outof the body through a second location, so that the distal and proximalends of the guidewire extend from the body, then pulling a device intoposition using the guidewire. The device to be positioned within thebody is coupled to the proximal end of the guidewire, and the device ispulled into the body by pulling on the distal end of the guidewire thatextends from the body. The device may be bimanually manipulated bypulling the guidewire distally, and an attachment to the device thatextends proximally, allowing control of both the proximal and the distalends. In this manner devices (and particularly implants such asinnerspinous distracters, stimulating leads, and disc slings) may bepositioned and/or manipulated within the body. Devices to modify tissuemay also be positioned or manipulated so that a target tissue within thebody is modified.

Devices and systems configured to be coupled to the proximal end of apull guidewire (or “pullwire”) are also described. In general, a systemfor pulling an implant or tissue modification device into position asdescribed herein may include a probe for positioning a guidewire intoposition, a guidewire/pullwire, a handle for the guidewire/pullwire, anda device having a distal end configured to couple to the pullwire and bepulled into position by the pullwire. The devices or implants may beadapted for use with the pullwire. For example the distal end of thedevices/implants may be configured to releaseably secure to the proximalend of the pullwire. Furthermore, the devices may be adapted so that theconnection with the guidewire is sufficient to withstand a substantialamount of pulling force that may be applied when positioning ormanipulating the device(s).

For example, the general devices and methods described herein may beused to position and/or manipulate devices involved in the treatment ofany of the following conditions: positioning/implanting stimulator leads(including anchoring them) within the body, and especially within thelateral recess or foramen; treatment of chronic total occlusions,including retrograde treatment (e.g., pull through); placement ofpedicle screw(s); accessing a facet joint for fusion (e.g., posteriorlateral gutters), implantation, etc.; spinal fusions, includingpercutaneously pulling in a rod between the screws; discectomy; removeor repair of disc herniation; pain management, including delivery ofdrug depot (e.g., ribbon, pod, electrodes, etc.), and particularlyplacement within spinal regions such as the facet joint; treatment ofspine tumors (e.g., cage); insertion/implantation of stem cells;implantation of interlaminar wires; rapid laminectomy (e.g., in/outtechnique); treatment of distal clavicle, including shoulderimpingement; treatment of entrapment Syndrome (e.g., carpel tunnel);removal of tumors, osteophites, around rib cage, ribs; thoracotomy;treatment of bone spurs; treatment of knees, includingpositioning/implanting drugs depots (e.g., steroids) and resurfacing ofthe joint; resurfacing of joints generally (spinal, etc.), includingresurfacing of cartilage and preparation of joint for implant(s);removal of adipose (fat) tissue (e.g., liposuction); reconstructivesurgeries (e.g., rhinoplasty, etc.); and the like.

Described below are particular examples, including devices adapted foruse with these examples that illustrate methods of performing suchtreatments and therapies. For example, described herein are methods ofperforming inner spinous distraction. Inner spinous distraction may beperformed as part of another procedure, including a spinal decompressionprocedure, since it may enhance access to regions of the spine requiringdecompression.

Also described herein are devices and methods for implanting andanchoring an electrical lead. An electrical lead may be used to helptreat chronic pain. The devices and methods described herein may allowprecise implantation and anchoring of a lead. Adequate anchoring ofimplants (such as leads) is critical to prevent migration and eventualfailure of these devices.

Also described are methods of treating spinal bone such as facet joints.For example, described herein are methods of resurfacing adjacent facetjoints as part of a fusion procedure.

In another variation, method of performing discectomy are alsodescribed, which may also be performed as part of a separate procedure,or as part of a decompression procedure.

For example, described herein are methods for placing an inner spinousdistractor within a body using a pullwire having a tissue-penetratingdistal end and a proximal end. These methods may include: extending apullwire across an inner spinous ligament between two spinous processesso that the proximal end of the pullwire extends from a first positionoutside of the body, and the distal end of the pull wire extends from asecond position outside of the body; and pulling the distal end of thepullwire to pull a spinous process distractor from the first positioninto the inner spinous ligament between the two spinous processes.

The method may also include the step of coupling the proximal end of thepullwire to a distal end of the spinous process distractor. For example,the method may include coupling the proximal end of the pullwire to adistal end of a spinous process distractor delivery device. The step ofextending the pullwire may include percutaneously passing the pullwirethrough the body from a first opening in the body at the first positionto a second opening in body at the second position.

The method may also include detaching the distal end of the pullwirefrom the spinous process distractor. The pullwire may then be removedfrom body; in some variations the pullwire may remain coupled to aportion of the spinous process detractor delivery device, which may beremoved with the pullwire.

The method may also include pulling a sizer between the two spinousprocesses using the pullwire. The sizer may be used to determine theappropriate size spinous process distractor to use.

In some variations the method also includes locking the spinous processdistractor in position between the two spinous processes. The method mayalso include expanding the spinous processes distractor.

The step of extending a pullwire may include inserting a curved,cannulated probe between the spinous processes and passing the pullwirethrough the cannulated probe to extend from the distal end and out ofthe second opening out of the body. In some variations, the probe mayinclude an outer cannula and an inner cannula that is configure to beextend from the distal end of the outer cannula in a curved pathway.

Also described herein are methods of placing an inner spinous distractorwithin a body using a pullwire having a tissue-penetrating distal endand a proximal end, the method comprising: inserting a curved,cannulated probe between two spinous processes so that the tip of theprobe extends in a curved pathway through the inner spinous ligament;extending a pullwire through the probe so that a distal end of thepullwire extends out of the body while the proximal end extends from thebody proximally; removing the probe while leaving the pullwire inposition across the spinous ligament; and pulling the distal end of thepullwire to pull a spinous process distractor between the two spinousprocesses.

Also described herein are systems for inner spinous distraction, thesystem comprising: an inner spinous distractor configured to be pulledinto position through the inner spinous ligament between two spinousprocesses and to distract the two spinous processes; a pullwire having atissue-penetrating distal end and a coupler at the proximal end, thecoupler configured to couple to the inner spinous distractor so that thepullwire may be used to pull the inner spinous distractor into position;and a cannulated probe having a curved distal end, the probe configuredto position the pullwire between two spinous processes.

In some variations, the system also includes a sizer configured tocouple to the proximal end of the pullwire so that it can be pulledbetween two spinous processes.

The system may also include a distal handle configured to attach to thedistal end of the pullwire and to secure the tissue-penetrating distalend of the pullwire.

In some variations the system also includes an inner spinous distractordelivery tool configured to hold the inner spinous distractor fordelivery between two spinous processes, wherein the distal end of thedelivery tool comprises a coupler for coupling to the proximal end ofthe pullwire and the proximal end of the inner spinous distractordelivery tool comprises a proximal handle.

The system may also include a lock for securing the inner spinousdistractor in position between two spinous processes.

Also described herein are methods of implanting a lead for electricalstimulation adjunct to a target nerve tissue, the method comprising:extending a pullwire adjacent to the target nerve tissue so that theproximal end of the pullwire extends from a first position outside ofthe body, and the distal end of the pull wire extends from a secondposition outside of the body; coupling the distal end of the lead to theproximal end of the pullwire; and pulling the distal end of the pullwireto pull an electrical lead from the first position so that the lead isadjacent to the target nerve tissue.

The method may also include the step of anchoring the proximal anddistal end of the lead. For example, the step of anchoring the proximaland distal end of the lead may comprise expanding an expandable member,or inflating a balloon.

The method may also include de-coupling the distal end of the lead fromthe proximal end of the pullwire and withdrawing the pullwire distallyfrom the body.

The step of extending the pullwire may include passing the pullwire overa spinal pedicle. In some variations, the step of extending the pullwirecomprises passing the pullwire down the lateral recess between twospinal lamina.

The method may also include confirming the position of the target nerverelative to the path of the guidewire. For example, a nerve localizationdevice (including a plurality of electrodes for stimulating nerves thatare immediately near the localization device) may be used, for example,by pulling the neural localization device through the tissue using thepullwire.

Also described herein are electrical leads for pain management that areconfigured to be pulled into position distally and anchored distally andproximally. For example, such a lead may include: an elongate bodyhaving a distal coupling region configured to couple to the proximal endof a pullwire; a first anchoring element at the distal end configured toanchor the lead within the body; a second anchoring element at theproximal end configured to anchor the lead within the body; and aplurality of electrical contacts located between the proximal and distalanchors.

The electrical lead devices may also include a proximally-extendingelectrical connector configured to connect to an implantable pulsegenerator for applying energy to the plurality of electrical contacts.

Also described herein are systems for positioning and anchoring anelectrical lead relative to a patient's spinal nerves, the systemcomprising: an electrical lead comprising a distal connector configuredto be used to distally pull the lead adjacent to a target spinal nervetissue; a pullwire having a tissue-penetrating distal end and a couplerat the proximal end, the coupler configured to couple to the distalconnector of the electrical lead so that the pullwire may be used topull the electrical lead into position; and a cannulated probe having acurved distal end, the probe configured to position the pullwireadjacent to the target spinal nerve tissue.

In some variations the system includes a neural localization devicehaving a distal connector configured to couple to the coupler at theproximal end of the pullwire. In some variations the system furthercomprises a distal handle configured to attach to the distal end of thepullwire and to secure the tissue-penetrating distal end of thepullwire.

Also described herein are methods of fusing a facet joint using abimanual treatment device. For example, a method of fusing a facet jointusing a bimanual treatment device the method may include the steps of:extending a pullwire between two spinous processes so that the proximalend of the pullwire extends from a first position outside of the body,and the distal end of the pull wire extends from a second positionoutside of the body; coupling the distal end of a facet joint modifyingtreatment device to the proximal end of the pullwire; pulling the distalend of the pullwire to pull the facet joint modifying treatment devicefrom the first position so that the facet joint modifying treatmentdevice is adjacent to the facet joint; and reciprocating the facet jointmodifying treatment device by pulling distally on the pullwire andproximally on the facet joint modifying treatment device.

The method may also include the step of applying a filling materialbetween the facet joint. Filling materials may include cement (e.g.,bone cement), graft materials, or the like. The method may also includethe step of inserting a support between the facet joint by pulling thecage in distally using the pullwire. For example, the support maycomprise a cage, and/or an expandable member.

In some variations the method includes the step of cutting the superiorspinous process of the facet.

Any appropriate facet joint modifying treatment device may be used,including a facet joint modifying treatment device having a bone-cuttingsurface.

Also described herein are devices, systems and method for positioning,actuating and exchanging various tissue access, treatment, andlocalization devices. In particular, described herein are exchangesystems using a guidewire which may be used to both position and/oractuate a variety of such devices, while allowing exchange of suchdevices. Systems including these guidewires may be referred to herein as“exchange systems”, “guidewire systems,” “guidewire exchange systems” orthe like.

For example, described herein are methods of exchanging a surgicaldevice while treating a patient. These methods may include the steps ofadvancing a guidewire at least partially around a target tissue in apatient so that the proximal end of the guidewire extends from a firstsite on the patient and the distal end of the guidewire extends from asecond site on the patient, coupling the proximal end of the guidewireon or near the distal end of a first surgical device, positioning thefirst surgical device by pulling the distal end of the guidewire,de-coupling the proximal end of the guidewire from the first surgicaldevice, coupling the proximal end of the guidewire to a second surgicaldevice, and positioning the second surgical device by pulling the distalend of the guidewire.

In some variations, the method may also include the step of withdrawingthe first surgical device from the patient by pulling on the proximalend of the first surgical device. For example, the surgical device maybe a relatively elongate device having a flexible distal end. The distalregion of the device is preferably low-profile, and may be flat or thin.Surgical devices appropriate for use with the methods and systemsdescribed herein may be pulled into the subject using the guidewire, sothat the proximal end of the surgical device (or a connector connectedto the proximal end) remains outside of the patient. Thus, the firstsurgical device comprises an elongate surgical device having a flexibledistal end. For example, the surgical device may be a tissuemodification device (e.g., having a surface including one or more tissuemodification elements).

The method may also include the step of urging the first surgical deviceagainst the target tissue by applying tension to either or both of thefirst surgical device extending from the first site and the guidewireextending from the second site. Similarly, the method may also includethe step of urging the second surgical device against the target tissueby applying tension to either or both of the second surgical deviceextending from the first site and the guidewire extending from thesecond site.

The step of advancing the guidewire may include advancing the guidewirethrough a spinal foramen, particularly an intervertebral foramen.

Neural tissue localization may also be included as a part of the methodsdescribed herein. It may be particularly beneficial to confirm thatneural tissue (e.g., a nerve) is not located between the target tissueand the guidewire before performing a procedure on the target tissue.Any appropriate tissue localization step may be used. For example, thetissue adjacent to the pathway of the guidewire may be directlyvisualized (using an endoscope, etc.), or indirectly visualized (using amedical imaging technology). Electrical tissue stimulation may be used.Examples of tissue localization methods, devices and systems that may beused can be found in U.S. patent application Ser. No. 12/060,229 (titled“SYSTEM AND APPARATUS FOR NEURAL LOCALIZATION”), filed Mar. 31, 2008,now U.S. Pat. No. 7,959,577, herein incorporated by reference in itsentirety. In some variations, an electrical current is applied to thetissue adjacent the pathway of the guidewire to stimulate a nerve.Stimulation can be detected (e.g., by muscle twitch, EMG, etc.). Thus,the step of advancing the guidewire may include the step of confirmingthat a non-target nerve is not between the target tissue and the path ofthe guidewire, and in some variations the step of confirming that anon-target nerve is not between the target tissue and the path of theguidewire comprises applying electrical energy to the tissue.

Also described herein are methods of exchanging a surgical device whiletreating a patient that include the steps of: advancing a guidewirethrough an intervertebral foramen and at least partially around a targettissue in a patient so that the proximal end of the guidewire extendsfrom a first site on the patient and the distal end of the guidewireextends from a second site on the patient, coupling the proximal end ofthe guidewire on or near the distal end of a first surgical device,pulling the distal end of the guidewire to position the first surgicaldevice adjacent the target tissue, removing the first surgical devicefrom the patient while leaving the guidewire in the patient, de-couplingthe proximal end of the guidewire from the first surgical device,coupling the proximal end of the guidewire to a second surgical device,and pulling the distal end of the guidewire to position the secondsurgical device.

Also described herein are methods of treating a patient, the methodincluding the step of advancing a distal end of a guidewire into thepatient's body from a first site, advancing the distal end at leastpartially around a target tissue, extending the distal end of theguidewire out of the body from a second site, while maintaining aproximal end of the guidewire outside the body at the first site,coupling the proximal end of the guidewire on or near a distal end of asurgical device, and pulling the distal end of the guidewire to guide atleast a portion of the surgical device to a desired position adjacent tothe target tissue.

In many of the methods described herein, the guidewire is insertedthrough the patient's body so that both the proximal and distal ends ofthe guidewire extend from the body, typically (but not necessarily) fromseparate entry and exit sites. The path that the guidewire takes iscurved or bent, and the bend occurs adjacent to the target tissue. Thismay allow the guidewire or a device attached to the guidewire to beurged specifically against the target tissue by applying tension. Forexample, one or both ends of the guidewire (or a device attached to theguidewire) may be pulled, urging the device against the target tissue.Thus, the method may include the step of urging the surgical deviceagainst the target tissue by applying tension to either or both of thesurgical device extending from the first site and the guidewireextending from the second site.

The step of coupling the proximal end of the guidewire on or near thedistal end of the surgical device may include coupling the proximal endof the guidewire to the surgical device with at least one couplingmember. For example, the step may include engaging a guidewire couplingmember on the surgical device with the distal end of the guidewire.

In some variations, the method also includes the step of locking theproximal end of the guidewire on or near a distal end of a surgicaldevice. The guidewire may be permanently or releasably locked to thesurgical device. For example, the guidewire may be permanently locked bycrimping the coupling member or be lodging the guidewire (e.g., theshaped proximal end of the guidewire) within the coupling member of thesurgical device.

The method may also include the step of performing a surgical procedureon the target tissue using the surgical device. For example, the step ofperforming a surgical procedure may include reciprocating the surgicaldevice by pulling on either or both of the surgical device extendingfrom the first site and the guidewire extending from the second site.

The method may also include the step of withdrawing the surgical deviceproximally from the patient. In some variations, the method alsoincludes de-coupling the proximal end of the guidewire from the surgicaldevice and coupling the proximal end of the guidewire on or near adistal end of a second surgical device.

Also described herein are methods for guiding at least a portion of asurgical device to a desired position between two tissues in a patient'sbody. These methods may include the steps of: advancing a distal end ofa guidewire into the patient's body, between two tissues, and out of thebody, while maintaining a proximal end of the guidewire outside thebody, coupling the proximal end of the guidewire with at least onecoupling member on or near a distal end of a surgical device, andpulling the distal end of the guidewire to guide at least a portion ofthe surgical device to a desired position between the two tissues.

Also described herein are methods for performing a procedure on a targettissue in a patient's body. These methods may include coupling aproximal end of a guidewire with at least one coupling member on or neara distal end of a surgical device, pulling a distal end of the guidewireto guide at least a portion of the surgical device to a desired positionbetween the two tissues, such that an active portion of the surgicaldevice faces target tissue and an atraumatic portion of the surgicaldevice faces non-target tissue, and performing a procedure on the targettissue, using the surgical device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a vertebra with the cauda equina shown in crosssection and two nerve roots branching from the cauda equina to exit thecentral spinal canal and extend through intervertebral foramina oneither side of the vertebra.

FIG. 2A is a cross-sectional view of a patient's back and a side view ofa flexible tissue modification device in position in a spine, accordingto one embodiment of the present invention.

FIG. 2B is a diagrammatic view of a generic portion of a patient's body,showing target and non-target tissue, with the device of FIG. 2A inposition to modify target tissue, according to one embodiment of thepresent invention.

FIG. 2C is a side view of a tissue modification device, according to analternative embodiment of the present invention.

FIG. 2D is a side view of a tissue modification device, according toanother alternative embodiment of the present invention.

FIG. 3A is a view of a kit or system for modifying tissue, according toone embodiment of the present invention.

FIG. 3B is a side view of a portion of the kit of FIG. 3B.

FIGS. 4A-4E demonstrate a method for inserting and using a flexibletissue modification device to modify tissue while inhibiting damage tonon-target tissue, according to one embodiment of the present invention.

FIG. 5A is a perspective view of a flexible portion of a tissuemodification device, according to one embodiment of the presentinvention.

FIGS. 5B and 5C are end-on and side views of blade and substrateportions of the portion of the device of FIG. 5A.

FIG. 6 is a perspective view of a portion of a flexible substrate and awire saw tissue modifying member of a tissue modification device,according to one embodiment of the present invention.

FIG. 7 is a perspective view of a portion of a flexible substrate andmultiple wire saw tissue modifying members of a tissue modificationdevice, according to an alternative embodiment of the present invention.

FIG. 8 is a perspective view of a portion of a flexible substrate and anabrasive surface tissue modifying member of a tissue modificationdevice, according to an alternative embodiment of the present invention.

FIG. 9 is a perspective view of a portion of a flexible substrate andmultiple tooth-like tissue modifying members of a tissue modificationdevice, according to an alternative embodiment of the present invention.

FIG. 10 is a perspective view of a portion of a flexible substrate and atwo-blade tissue modifying member of a tissue modification device,according to an alternative embodiment of the present invention.

FIG. 11 is a perspective view of a portion of a flexible substrate andmultiple shark-tooth-shaped tissue modifying members of a tissuemodification device, according to an alternative embodiment of thepresent invention.

FIG. 12 is a perspective view of a portion of a flexible substrate andmultiple cheese-grater-shaped tissue modifying members of a tissuemodification device, according to an alternative embodiment of thepresent invention.

FIG. 13 is a perspective view of a portion of a flexible substrate andmultiple raised tissue modifying members of a tissue modificationdevice, according to an alternative embodiment of the present invention.

FIG. 14 is a perspective view of a portion of a flexible substrate andmultiple raised-flap tissue modifying members of a tissue modificationdevice, according to an alternative embodiment of the present invention.

FIG. 15 is a perspective view of a portion of a flexible substrate andmultiple rounded tissue modifying members of a tissue modificationdevice, according to an alternative embodiment of the present invention.

FIG. 16 is a perspective view of a portion of a flexible substrate andmultiple raised-flap tissue modifying members of a tissue modificationdevice, according to an alternative embodiment of the present invention.

FIG. 17 is a perspective view of a portion of a flexible substrate andmultiple, differently shaped tissue modifying members of a tissuemodification device, according to an alternative embodiment of thepresent invention.

FIG. 18 is a perspective view of a portion of a flexible substrate andbarbed-hook and raised-flap tissue modifying members of a tissuemodification device, according to an alternative embodiment of thepresent invention.

FIG. 19 is a perspective view of a portion of a wire mesh flexibletissue modification device, according to an alternative embodiment ofthe present invention.

FIG. 20 is a perspective view of a portion of a flattened, hollow,flexible tissue modification device, according to an alternativeembodiment of the present invention.

FIG. 21 is a perspective view of a portion of a flexible substrate andcheese-grater-shaped tissue modifying members coupled with a tissuecapture member of a tissue modification device, according to analternative embodiment of the present invention.

FIG. 22 is a perspective view of a portion of a moveable-link flexibletissue modification device, according to an alternative embodiment ofthe present invention.

FIG. 23 is a perspective view of a portion of a flexible substrate andtissue modifying member of a tissue modification device, according to analternative embodiment of the present invention.

FIG. 24 is a perspective view of a portion of a flexible substrate andtissue modifying member of a tissue modification device, according to analternative embodiment of the present invention.

FIGS. 25A and 25B are perspective views of a portion of a flexiblesubstrate and tissue modifying members of a tissue modification device,according to an alternative embodiment of the present invention.

FIGS. 26A-26C are side views of a portion of a flexible tissue devicewith a tissue capture member, demonstrating a method for tissuemodification, according to one embodiment of the present invention.

FIG. 27A is a side view demonstrating a method of making a portion of aflexible tissue modification device, according to one embodiment of thepresent invention.

FIGS. 27B and 27C are side and perspective views, respectively, of aportion of a tissue modification device with a tissue capture member,such as may be constructed using a method as in FIG. 27A.

FIGS. 28A and 28B are side views of a portion of a flexible tissuemodification device with a tissue capture member, according to oneembodiment of the present invention.

FIG. 28C is a side view of a portion of a flexible tissue modificationdevice with a tissue capture member, according to an alternativeembodiment of the present invention.

FIG. 29A is a perspective view of a flexible tissue modification devicewith a floating tissue capture member, according to one embodiment ofthe present invention.

FIGS. 29B and 29C are end-on views of a flexible tissue modificationdevice with a floating tissue capture member, according to analternative embodiment of the present invention.

FIG. 30 is a side view of a portion of a hollow, flexible tissuemodification device, according to one embodiment of the presentinvention.

FIG. 31 is a side, cross-sectional view of a portion of a hollow,flexible tissue modification device with a tissue transport member,according to one embodiment of the present invention.

FIG. 32 is a side, cross-sectional view of a portion of a hollow,flexible tissue modification device with a tissue transport member,according to an alternative embodiment of the present invention.

FIG. 33 is a side, cross-sectional view of a portion of a hollow,flexible tissue modification device with a tissue transport member,according to an alternative embodiment of the present invention.

FIG. 34A is a side, cross-sectional view of a portion of a hollow,flexible tissue modification device with a tissue transport member,according to an alternative embodiment of the present invention.

FIG. 34B is a side view of a proximal ratcheting mechanism portion ofthe hollow, flexible tissue modification device of FIG. 34A.

FIG. 34C is a top view of a portion of the substrate of the device ofFIG. 34B.

FIG. 35 is a side, cross-sectional view of a portion of a hollow,flexible tissue modification device with a tissue transport member,according to an alternative embodiment of the present invention.

FIGS. 36A-36B show one variation of a tissue modification device havinga tissue collection region.

FIG. 36C shows another variation of a tissue modification device havinga tissue collection region.

FIGS. 37A and 37B show another variation of a tissue modification devicehaving a tissue collection region.

FIGS. 38A and 38B show cross-sectional views of one variation of aremovable and expandable tissue collection region.

FIGS. 39A and 39B show cross-sectional views of one variation of aremovable and expandable tissue collection region, and FIG. 39C is across-section through just the removable surface forming part of thetissue collection region.

FIGS. 40A and 40B show cross-sectional views of one variation of aremovable and expandable tissue collection region; and FIG. 40C is aside perspective view of a removable major surface that is expandable.

FIGS. 41A and 41B illustrate assembly of one variation of a tissuemodification device including an expandable and removable tissuecollection region.

FIG. 42 is a perspective view of another variation of a tissuemodification device including a removable tissue collection region.

FIG. 43 is a perspective view of another variation of a tissuemodification device including a removable tissue collection region.

FIG. 44A is a perspective view of another variation of a tissuemodification device including a tissue collection region; FIG. 44B is asection through the tissue modification device shown in FIG. 44A, andFIG. 44C is a perspective view of a cutting surface of the tissuemodification device shown in FIG. 44A.

FIG. 45 is a side view of a tissue modification device in a position forperforming a tissue modification procedure, showing a generic bone, softtissue and non-target tissue, according to one embodiment of the presentinvention.

FIG. 46 is a side view of a tissue modification device with verticallyoriented blades, according to one embodiment of the present invention.

FIG. 47 is a perspective view of a flexible portion of a tissuemodification device with vertically oriented blades, according to oneembodiment of the present invention.

FIG. 48 is a top view of a flexible portion of a tissue modificationdevice with vertically oriented blades, according to one embodiment ofthe present invention.

FIGS. 49A-49D are end-on views of flexible portions of various tissuemodification devices with vertically oriented blades, according tovarious alternative embodiments of the present invention.

FIG. 50 is a top view of a flexible portion of a tissue modificationdevice with vertically oriented blades, according to an alternativeembodiment of the present invention.

FIGS. 51A-51E are end-on views of a flexible portion of a tissuemodification device with vertically oriented blades, demonstrating amethod for moving the device back and forth laterally in anintervertebral foramen, according to one embodiment of the presentinvention.

FIG. 52 is a perspective view of a double-blade member for attachment toa flexible portion of a tissue modification device, according to oneembodiment of the present invention.

FIG. 53 is a perspective view of a double-blade member for attachment toa flexible portion of a tissue modification device, according to analternative embodiment of the present invention.

FIG. 54 is a perspective view of a twelve-blade member for attachment toa flexible portion of a tissue modification device, according to analternative embodiment of the present invention.

FIG. 55 is a perspective view of an eight-blade member for attachment toa flexible portion of a tissue modification device, according to analternative embodiment of the present invention.

FIG. 56 is a side view of a flexible portion of a tissue modificationdevice with vertically oriented blades, according to one embodiment ofthe present invention.

FIG. 57 is a perspective view of a flexible portion of a tissuemodification device with vertically oriented blades, according to analternative embodiment of the present invention.

FIG. 58 is a top view of a flexible portion of a tissue modificationdevice, demonstrating a method for forming vertically oriented blades,according to an alternative embodiment of the present invention.

FIGS. 59-76 are side views of various configurations of blades for usewith tissue modification devices, according to various alternativeembodiments of the present invention.

FIGS. 77-82 are cross-sectional views of various configurations ofblades for use with tissue modification devices, according to variousalternative embodiments of the present invention.

FIGS. 83A and 83B illustrate how tension in a flexible portion of atissue modification device bent over a target tissue can urge blades orother tissue modification devices into the target tissue, and how torqueto the rigid portion of the tissue modification device can maintain oralter an orientation of the flexible member and inhibit flipping of theflexible member.

FIG. 84A is a perspective view schematically illustrating shifting ofthe flexible member laterally along a target tissue by laterallytranslating the proximal rigid portion, and/or by pivoting the rigidportion about tissues along the site of insertion.

FIG. 84B schematically illustrates lateral translation and pivoting ofthe rigid portion to effect shifting of the flexible portion relative tothe target tissue, and also schematically illustrates an optional rigidtubular shaft coupled to a distal handle to similarly allow shifting ofthe distal end of the flexible portion and provide enhanced control overtarget tissue remodeling and/or removal.

FIG. 85 is a cross section through the posterior aspect of the lumbarspine;

FIG. 86 is a sagittal section through the lumbar spine;

FIGS. 87 a, b, c are sagittal views through a patient's spine,illustrating a prior art method for epidural needle insertion, a loss ofresistance method;

FIG. 87 a illustrates a needle inserted to an interspinal ligament.

FIG. 87 b illustrates constant pressure applied on the syringe plunger.

FIG. 87 c illustrates saline injected into the epidural space.

FIG. 88 is a cross-sectional view through a patient's spine,illustrating two prior art variations of the method of FIGS. 87 a, b, c;

FIG. 89 is an illustration of standard Touhy epidural needle tips;

FIG. 90 a-c are schematic side views illustrating a method andapparatus, in accordance with the present invention, for covering with acap and blunting the sharp tip of an epidural needle post-insertion;

FIG. 91 a-b are also schematic side views of variations of the apparatusof FIG. 90 with a method for also limiting the depth of insertion ofcannula, access portal, or needle;

FIG. 92 a-c are schematic side views illustrating a method and apparatusin accordance with the present invention for covering with a cap andblunting the tip of the epidural needle post-insertion, and optionallyconverting the epidural needle to an epidural endoscope, for safefurther advancement of the needle into the epidural space;

FIG. 93 a-c are also schematic side views of variations of the apparatusof FIG. 92;

FIG. 94 a-e are also schematic side views of variations of the apparatusof FIG. 90 or 92;

FIG. 95 a-d are also schematic side views of variations of the apparatusof FIG. 92;

FIGS. 96 a-c are schematic side views of variations of the apparatus ofFIG. 90 or 92;

FIGS. 96 d-e are schematic side views of an epidural portal over needleapparatus, as shown in FIGS. 96 a, b, c; with a distal anchor engagedanterior to the ligamentum flavum, when the portal has been insertedover the needle, into the epidural space;

FIG. 97 a-e are schematic side views of variations of the apparatus ofFIG. 90 or 92;

FIG. 98 a is a schematic side view, partially in section, of variationsof the apparatus, illustrating methods of safely utilizing the apparatus(e.g., safe tool access) for safe placement and use of surgical tools inor around the epidural space;

FIG. 98 b are side views, partially in section, illustrating a methodand apparatuses for safe placement of a tool or working channel into theepidural space;

FIG. 99 are side views illustrating apparatuses that include a doublebarreled epidural needle, with the epidural needle as the most distalpoint, and with the working channel the more proximal tip. This systemmay also be converted to an endoscope and may be used for safe placementof instruments into the epidural space;

FIGS. 100-102 are cross-sectional views through a patient's spine,illustrating a method and apparatus for placement of a double barreledepidural needle or endoscope, the sharp tip of which has been covered inFIG. 101, and thereby blunted, for safe advancement towards the lateralrecess and neural foramina. The blunted epidural needle apparatus maycontain a fiberoptic cable for direct visualization, in a preferredembodiment;

FIG. 103 is a cross-sectional view through a patient's spine thatillustrates a method, following FIGS. 100-102, for placement of aworking backstop or barrier into the lateral recess and/or neuralforamina. The barrier or backstop may contain elements for neurallocalization;

FIGS. 104 a-b and 105 a-b are cross-sectional views through a patient'sspine that illustrate alternative methods and apparatuses for placementof a working backstop or barrier to enable safe tissue resection,ablation, abrasion or remodeling;

FIG. 106 is a cross-sectional view through a patient's spine thatillustrates a tool inserted through the working channel (example shows ashaver or burr), with its tip in position for tissue removal ordebridement, adjacent to a protective working backstop or barrier.

FIGS. 107 a-107 d are schematic views of a working backstop or barrierapparatus, including an optional rail for controlled tool placement inrelation to the barrier, and an optional conductive element for neurallocalization.

FIG. 107 b is a frontal view from above;

FIG. 107 c is a front view;

FIG. 107 d is a frontal view of the working backstop or barrierapparatus folded for compact delivery;

FIG. 108 is a cross-sectional view through a patient's spine thatillustrates a methods and apparatuses for providing neural stimulationand neural localization, within a working backstop or barrier, and/orwithin a tool (a bone burr placed adjacent to a spinal bone spur in thelateral recess, in this illustrative example), for safety in tissueresection, abrasion or remodeling;

FIGS. 109-116 are cross-sectional views through a patient's spine,illustrating a method and apparatus for placement and use of elementsfor selective surgical removal of tissue;

FIGS. 117-120 are cross-sectional views through a patient's spine,illustrating a variation of the method and apparatus of FIGS. 109-116;

FIGS. 121 a-d are cross-sectional views through a patient's spine,illustrating another variation of the method and apparatus of FIGS.109-116; FIG. 121 e shows a cross-section through a placement apparatusas indicated in FIG. 37B.

FIG. 122 are a detailed view and a close up of the cross section of apreferred embodiment of the apparatus used in FIG. 37D;

FIG. 123 an alternative embodiment of the apparatus of FIG. 122;

FIGS. 124-129 are partial cross-sectional views through a patient'sspine, illustrating a method for use with single or multiple lumendelivery systems, for placement of an abrasion apparatus through theneural foramina for selective surgical removal of tissue;

FIGS. 130-142 are cross-sectional views through a patient's spine,illustrating a variation of the methods and apparatus of FIGS. 124-129,which may also be used with single or multiple lumen delivery systems;

FIG. 143 is a cross-sectional view through a patient's spine,illustrating a methods and apparatus that, under tension, anchors andsuspends the working sheath or protective sleeve that covers theneuroforaminal abrasion device;

FIG. 144 is a cross-sectional view through a patient's spine,illustrating a method and apparatus that, under tension, provides apercutaneous compression dressing over the abraded area. In thisillustration, the compression dressing is the same working sheath orprotective sleeve that had covered the neuroforaminal abrasion device;

FIG. 145 is a schematic cross-sectional view through a patient's spine,illustrating a method and apparatus for achieving neural localizationprior to or during use of the tissue removal apparatus;

FIG. 146 a-b are schematic views of additional apparatus, showing aspool or reel to reel configuration of a portion of the device that maybe utilized for selective surgical removal of tissue;

FIGS. 147-154 are schematic cross-sectional views through a patient'sspine of a method and apparatus for a posterior midline or paramedianapproach to placement of a posterior elements compression, retraction orretention device around the facet complex, through the neural foramina;

FIG. 155 a-b are schematic cross-sectional views through a patient'sspine illustrating a posterior lateral approach to placement of thespinal compression, retraction or retention apparatuses;

FIG. 156 a-b are schematic cross-sectional views through a patient'sspine of a fully implanted compression or retraction remodelingapparatus or compression dressing apparatus;

FIG. 157 is a schematic cross-sectional view through a patient's spineof an apparatuses for a compression remodeling strap integrated with aworking backstop or barrier.

FIG. 158 is a cross-sectional view through a patient's spine that showsa facet drill with a ligament retraction device around a workingbackstop, and demonstrates a image guided drill used in conjunction withthe backstop;

FIGS. 159-162 are schematic views of cable strap configurations fortemporary removable, permanent, or biodegradable compression dressingsor remodeling tools;

FIGS. 163-164 are schematic cross-sectional and lateral views through apatient's spine of apparatuses for temporary or permanent retraction andretention of the ligamentum flavum;

FIG. 165A-C are sagittal cryosection images through three cadavericspines (images courtesy of Wolfgang Rauschning, Md.) that illustratepathological anterior bulging and “buckling” of the ligamentum flavum,encroaching on the spinal canal or lateral recess, a frequentcontributing factor in spinal stenosis. In circumstances when similarlyprotruding ligamentum flavum impinges neural and neurovascularstructures in the spinal canal, lateral recess, or neural foramina, thenretraction of said ligaments, as in FIGS. 163 and 164 may be beneficialto the patient;

FIGS. 166 a-166 c are cross-sectional views through a protective sleeveor sheath, compact during insertion (b), and expanded (c) by passing theapparatus through its lumen;

FIG. 167 a-c are schematic cross section views of additional apparatusthat may be utilized for selective surgical removal of tissue;

FIG. 168 a-f are schematic cross section views of additional apparatusthat may be utilized for selective surgical removal of tissue, andsubsequently as a compression dressing, with the ability to act as atherapeutic drug depot;

FIG. 169 a-c are schematic cross section views of additional apparatusthat may be utilized for selective surgical removal of tissue;

FIG. 170 is a schematic cross section views of additional apparatus thatmay be utilized for selective surgical removal of tissue;

FIG. 171 a-c are close-up schematic views of the resecting element inFIG. 170 that may be utilized for selective surgical removal of tissue;

FIGS. 172-177 are schematic lateral views of additional apparatus thatmay be utilized for visualization in the epidural space, enabling theselective surgical removal of tissue;

FIG. 172 a-d illustrate an embodiment of an endoscope in a clear tippedcannula;

FIG. 173 a-b illustrate an embodiment of a O-degree endoscope rotated inunison with a curved, clear tipped cannula;

FIG. 174 a-b illustrate an embodiment of a 30-degree endoscope rotatedseparately inside of a clear tipped cannula;

FIGS. 175 a-c illustrate various embodiments of a clear tipped cannulawith a clear shaft;

FIGS. 175 d-f illustrate various embodiments of a clear tipped cannulawith an opaque shaft;

FIG. 176 a-d illustrate an embodiment of a clear tipped cannula with aflexible neck;

FIG. 177 illustrates an embodiment of an endoscope with a built-in clearcover (e.g., a combination device embodiment);

FIGS. 178-183 are schematic lateral views of similar apparatus forvisualization in the epidural space, along with additional method andapparatus that enable the safe placement and use of tools for selectivesurgical ablation, resection, abrasion and remodeling of tissue;

FIG. 178 a-b illustrate various embodiments of a clear tipped cannulawith a free adjacent tool;

FIG. 179 a-b illustrate various embodiments of a clear tipped cannulawith an attached adjacent tool;

FIG. 180 a illustrates an embodiment of a clear tipped cannula with aworking channel for a tool;

FIG. 180 b illustrates an embodiment of a clear tipped cannula with anerve stimulator at a working channel exit;

FIG. 181 a-c illustrate various embodiments of cannulas with a nervestimulator at the tip (e.g., EMG sensors peripherally placed);

FIG. 182 a-b illustrate various embodiments of a clear tipped cannulawith a nerve stimulator at a tip of the free tool; and

FIG. 183 a-b illustrate various embodiments of a clear tipped cannulawith a nerve stimulator at a tip of the free or attached tool.

FIG. 184 is a cross-sectional view of a portion of a patient's back andspine, showing part of a vertebra and apparatus in place for modifyingtissue according to one embodiment of the present invention;

FIG. 185A is a perspective view of a tissue modification deviceaccording to one embodiment of the present invention;

FIG. 185B is a perspective view of a portion of the tissue modificationdevice of FIG. 185A;

FIG. 185C is a top view of the portion shown in FIG. 185B;

FIG. 185D is a side view of the portion shown in FIGS. 185B and 185C;

FIGS. 185E and 185F are cross-sectional views of a portion of the tissuemodification device taken through lines A-A and B-B, respectively, shownin FIG. 185C;

FIG. 185G is a perspective view of a portion of the tissue modificationdevice of FIGS. 185B-185F, shown with a blade of the device in a closedposition according to one embodiment of the present invention;

FIG. 185H is a top view of the portion shown in FIG. 185G;

FIG. 185I is a side view of the portion shown in FIGS. 185G and 185H;

FIG. 186A is a perspective view of a tissue modification deviceaccording to one embodiment of the present invention;

FIG. 186B is a perspective view of a portion of the tissue modificationdevice of FIG. 186A;

FIG. 186C is a close-up, perspective view of a portion of the tissuemodification device of FIGS. 186A and 186B, showing a tissue modifyingmember according to one embodiment of the present invention;

FIGS. 187A-187D are cross-sectional views of a spine and demonstrate amethod for using a tissue modification device according to oneembodiment of the present invention;

FIG. 188A is a cross-sectional view of a portion of a patient's spineand back, with apparatus for modifying tissue in position for modifyingspinal tissue and with a distal portion of the apparatus anchoredoutside the patient according to one embodiment of the presentinvention;

FIG. 188B is a cross-sectional view of a portion of a patient's spineand back, with apparatus for modifying tissue in position for modifyingspinal tissue and with a distal portion of the apparatus anchored insidethe patient according to one embodiment of the present invention;

FIGS. 189A-189S are cross-sectional views of a portion of a patient'sspine and back, demonstrating a method for introducing apparatus formodifying spinal tissue to an area in the spine for performing thetissue modification according to one embodiment of the presentinvention;

FIGS. 190A-190F are cross-sectional views of a portion of a patient'sspine and back, demonstrating a method for introducing apparatus formodifying spinal tissue to an area in the spine for performing thetissue modification according to an alternative embodiment of thepresent invention;

FIGS. 191A-191B are cross-sectional views of a portion of a patient'sspine and back, demonstrating a method for introducing apparatus formodifying spinal tissue to an area in the spine for performing thetissue modification according to an alternative embodiment of thepresent invention;

FIG. 192A is a perspective view of a distal portion of an introducersheath according to one embodiment of the present invention;

FIGS. 192B and 192C are perspective and cross-sectional views,respectively, of a tissue shield device according to one embodiment ofthe present invention; and

FIGS. 192D and 192E are perspective and cross-sectional views,respectively, of a tissue shield device according to an alternativeembodiment of the present invention.

FIG. 193A is a perspective view of a mesh-type barrier device deployingfrom a sheath according to one embodiment of the present invention.

FIG. 193B is a top view of the mesh-type barrier device of FIG. 193A inits free state, prior to loading in a sheath.

FIG. 193C is a perspective view of a flexible tab-type barrier devicedeploying from a sheath according to an alternative embodiment of thepresent invention.

FIG. 193D is a top view of the flexible tab-type barrier device of FIG.193C in its free state, prior to loading in a sheath.

FIG. 193E is a perspective view of a slit-type barrier device deployingfrom a sheath according to an alternative embodiment of the presentinvention.

FIG. 193F is a top view of the slit-type barrier device of FIG. 193E inits free state, prior to loading in a sheath.

FIG. 193G is a perspective view of a rib-type barrier device deployingfrom a sheath according to an alternative embodiment of the presentinvention.

FIG. 193H is a top view of the rib-type barrier device of FIG. 193G inits free state, prior to loading in a sheath.

FIG. 193I is a perspective view of a sheet-type barrier device deployingfrom a sheath according to an alternative embodiment of the presentinvention.

FIG. 193J is a top view of the sheet-type barrier device of FIG. 193I inits free state, prior to loading in a sheath.

FIG. 193K is a perspective view of a bar-type barrier device deployingfrom a sheath according to an alternative embodiment of the presentinvention.

FIG. 193L is a top view of the bar-type barrier device of FIG. 193K inits free state, prior to loading in a sheath.

FIG. 194A is a perspective view of a barrier device deployed by means ofa slider according to one embodiment of the present invention.

FIG. 194B is a perspective view of a portion of the barrier device ofFIG. 194A, in its free state.

FIG. 194C is a cross-sectional view of the barrier device of FIG. 194Athrough line C-C

FIG. 195A is a perspective view of a barrier device deployed by means ofseparable groove according to one embodiment of the present invention.

FIG. 195B is a perspective view of the distal tip of the barrier deviceof FIG. 195A, showing the device prior to deployment.

FIG. 196A is a perspective view of a barrier device with interdigitatingteeth according to one embodiment of the present invention.

FIG. 196B is a magnified view of an interdigitating tooth of FIG. 196A;

FIG. 196C is a top view of the interdigitating teeth of the barrierdevice of FIG. 196A.

FIG. 197A is a perspective view of a barrier device with a tapered tipand guidewire according to one embodiment of the present invention.

FIG. 197B is a cross-sectional view of the barrier device of FIG. 197A,through line D-D.

FIG. 198A is a perspective view of a barrier device with a flexibleframe according to one embodiment of the present invention.

FIG. 198B is a cross-sectional view of the barrier device of FIG. 198A,through line E-E, with a smooth barrier device stored in the sheathaccording to one embodiment of the present invention.

FIG. 198C is a cross-sectional view of the barrier device of FIG. 198A,through line E′-E′, with a ruffled barrier device stored in the sheathaccording to an alternative embodiment of the present invention.

FIG. 198D is a cross-sectional view of the barrier device of FIG. 198A,through line E″-E″, with a rolled barrier device stored in the sheathaccording to an alternative embodiment of the present invention.

FIG. 198E is a cross-sectional view of the barrier device of FIG. 198A,through line F-F, at the middle of the smooth, stretched barrier deviceaccording to one embodiment of the present invention.

FIG. 198F is a cross-sectional view of the barrier device of FIG. 198A,through line F′-F′ at the middle of the loose barrier device accordingto one embodiment of the present invention.

FIG. 198G is a cross-sectional view of the barrier device depicted inFIG. 198A, through line F″-F″ at the middle of the bag-like barrierdevice according to one embodiment of the present invention.

FIG. 199 is a perspective view of a barrier device with a corrugatedshape according to one embodiment of the present invention.

FIG. 200 is a perspective view of a barrier device composed of complianttubes according to one embodiment of the present invention.

FIG. 201 is a perspective view of a barrier device with a self-expandingframe according to one embodiment of the present invention.

FIG. 202A is a perspective view of a barrier device with aself-expanding frame that has supplemental push rods according to oneembodiment of the present invention.

FIG. 202B is a top view of a push rod diverter according to oneembodiment of the present invention.

FIG. 203 is a perspective view of a barrier device with an enlargedself-expanding frame according to one embodiment of the presentinvention.

FIG. 204A is a perspective view of a barrier device with a rolledbarrier material on each arm of a self-expanding frame according to oneembodiment of the present invention.

FIG. 204B is a perspective view of the barrier device of FIG. 204A withthe material unrolled from each arm of the self-expanding frameaccording to one embodiment of the present invention.

FIG. 205 is a perspective view of a barrier device with an articulatedmechanism to expand the frame.

FIG. 206A is a perspective view of a delivery sheath for delivering abarrier device according to one embodiment of the present invention.

FIG. 206B is a perspective view of a barrier device with a 4-bar linkagein a compact state according to one embodiment of the present invention.

FIG. 206C is a perspective view of the barrier device of FIG. 206B in anexpanded state according to one embodiment of the present invention.

FIG. 206D is a perspective view of a barrier device with multiple 4-barlinkages in a compact state according to an alternative embodiment ofthe present invention.

FIG. 206E is a perspective view of the barrier device of FIG. 206D in aexpanded state according to one embodiment of the present invention.

FIG. 207A is a perspective view of a barrier device with multiple 4-barlinkages, actuated by a central member, in a compact state according toone embodiment of the present invention.

FIG. 207B is a perspective view of the barrier device of FIG. 207A,actuated by a central member, in an expanded state according to oneembodiment of the present invention.

FIG. 208A is a perspective view of a barrier device with flex-linkagesaccording to one embodiment of the present invention.

FIG. 208B is a perspective view of a flex-linkage with a strain-reliefloop according to one embodiment of the present invention.

FIGS. 208C-208E are a series of top views of a barrier device withflex-linkages under different loading configurations according to oneembodiment of the present invention.

FIGS. 209A and 209B are perspective views of a woven tube barrier devicein low-profile and expanded states, respectively, according to oneembodiment of the present invention.

FIGS. 210A and 210B are perspective views of a flat woven barrier devicein low-profile and expanded states, respectively, according to oneembodiment of the present invention.

FIGS. 211A and 211B are perspective views of a barrier device with apull-mechanism in low-profile and expanded states, respectively,according to one embodiment of the present invention.

FIG. 212A is a perspective view of a cylindrical housing for a barrierdevice in an un-deployed state according to one embodiment of thepresent invention.

FIG. 212B is a perspective view of the cylindrical housing of FIG. 212Aand a barrier device deployed from the housing according to oneembodiment of the present invention.

FIGS. 212C-212F are perspective views illustrating a method of deployingthe barrier device of FIGS. 212A and 212B between a hard tissuestructure and a soft tissue structure according to one embodiment of thepresent invention.

FIG. 213A is a perspective view of a woven wire barrier device in anelongated state according to one embodiment of the present invention.

FIG. 213B is an enlarged perspective view of a portion of the barrierdevice of FIG. 213A;

FIG. 213C is a perspective view of the barrier device of FIG. 213A in anexpanded/shortened state according to one embodiment of the presentinvention.

FIGS. 214A-214C are perspective views of a hydrogel material barrierdevice in the process of unrolling/expanding after exposure to a fluidaccording to one embodiment of the present invention.

FIGS. 215A-215C are perspective and side views of a barrier device madefrom a plurality of curved elements according to one embodiment of thepresent invention.

FIG. 216A is a perspective view of a barrier device with thin,expandable flexure members shown in an un-expanded state according toone embodiment of the present invention.

FIG. 216B is a perspective view of the barrier device of FIG. 216A in anexpanded state according to one embodiment of the present invention.

FIG. 216C is a side view of the expanded barrier device of FIG. 216B.

FIG. 217 is a perspective view of a delivery device containing anun-deployed barrier device according to one embodiment of the presentinvention.

FIGS. 217A and 217B are perspective and end-on views, respectively, of adeployed barrier device according to one embodiment of the presentinvention.

FIGS. 217C and 217D are perspective and end-on views, respectively, of adeployed barrier device according to an alternative embodiment of thepresent invention.

FIGS. 217E and 217F are perspective and end-on views, respectively, of adeployed barrier device according to an alternative embodiment of thepresent invention.

FIGS. 217G and 217H are perspective and end-on views, respectively, of adeployed barrier device according to an alternative embodiment of thepresent invention.

FIGS. 218A and 218B are perspective views of an inflatable bladderbarrier device in deflated and inflated states, respectively, accordingto one embodiment of the present invention.

FIGS. 219A-219E are perspective views of a barrier device including aninflatable bladder containing particles, illustrating inflation anddeflation of the device according to one embodiment of the presentinvention.

FIG. 219F is a perspective view of various particles which may be usedin various embodiments of the barrier device of FIGS. 219A-219E.

FIGS. 220A-220C are perspective and cross-sectional views of a barrierdevice including a bladder with a foam element to affect the bladdershape after inflation according to one embodiment of the presentinvention.

FIG. 221A is a perspective view of a dual channel introducer and a wedgebarrier device that expands the introducer according to one embodimentof the present invention.

FIGS. 221B and 221C are cross-sectional views of the dual channelintroducer and the wedge barrier device of FIG. 221A, through Line H-Hand Line I-I, respectively, according to one embodiment of the presentinvention.

FIG. 222A is a perspective view of a barrier device according to oneembodiment of the present invention.

FIG. 222B is a top view of a portion of a barrier device according to analternative embodiment of the present invention.

FIG. 222C is an end-on view of the barrier device of FIG. 222A.

FIG. 222D is an end-on view of the barrier device of FIG. 222B.

FIG. 223A is a perspective view of a barrier device made fromsphere-like elements, shown in an un-expanded state according to oneembodiment of the present invention.

FIG. 223B is a perspective view of the barrier device of FIG. 223A,shown in an expanded state.

FIG. 223C is a detailed perspective view of a portion of the barrierdevice of FIG. 223A.

FIG. 224 is a perspective view of a barrier device including a cover anda malleable wire.

FIGS. 225A and 225B are perspective views of a barrier device and atissue modification device according to one embodiment of the presentinvention.

FIGS. 226A and 226B are perspective views of a barrier device and atissue modification device according to an alternative embodiment of thepresent invention.

FIG. 227 is a perspective view of a barrier device and a tissuemodification device according to an alternative embodiment of thepresent invention.

FIG. 228 is a perspective view of a barrier device and a tissuemodification device according to an alternative embodiment of thepresent invention.

FIGS. 229A and 229B are end-on views of a barrier device according toalternative embodiments of the present invention.

FIGS. 229C-229E are end-on views of a barrier device guide memberaccording to alternative embodiments of the present invention.

FIGS. 230A-230C are end-on views of a barrier device guide memberaccording to alternative embodiments of the present invention.

FIGS. 230D-230G are end-on views of a barrier device according toalternative embodiments of the present invention.

FIGS. 231A and 231B are end-on views of a barrier device according toalternative embodiments of the present invention.

FIG. 232 is an end-on view of a barrier device and delivery deviceaccording to one embodiment of the present invention.

FIG. 233 is a left lateral view of the lumbar portion of a spine withsacrum and coccyx;

FIG. 234 is a left lateral view of a portion of the lumbar spine,showing only bone and ligament tissue and partially in cross section;

FIG. 235A is a cross-sectional view of a patient's back and spine with aside view of an articulating rongeur in place for performing a tissueremoval procedure, according to one embodiment of the present invention;

FIGS. 235B-235D are side views of the articulating rongeur of FIG. 235A,demonstrating a method for articulating the rongeur and advancing acutting blade, according to one embodiment of the present invention;

FIGS. 236A and 236B are side cross-sectional views of a distal portionof an articulating rongeur, demonstrating articulation, according to oneembodiment of the present invention;

FIGS. 237A and 237B are side cross-sectional views of a distal portionof an articulating rongeur, demonstrating articulation, according to analternative embodiment of the present invention;

FIG. 238A is a side cross-sectional view of a distal portion of anarticulating rongeur, according to an alternative embodiment of thepresent invention;

FIG. 238B is a magnified side cross-sectional view of a portion of FIG.238B;

FIG. 238C is an end-on view of the portion of the articulating rongeurof FIG. 238B, from the perspective labeled A in FIG. 238B;

FIG. 239 is a side cross-sectional view of an articulating rongeur,according to an alternative embodiment of the present invention;

FIG. 240 is a side cross-sectional view of an articulating tissuecutting device having a reciprocating file tissue cutter, according toone embodiment of the present invention;

FIG. 241 is a perspective view of an articulating tissue cutting devicehaving a reciprocating file tissue cutter, according to an alternativeembodiment of the present invention;

FIG. 242 is a perspective view of an articulating tissue cutting devicehaving a reciprocating file tissue cutter, according to an alternativeembodiment of the present invention; and

FIG. 243 a side cross-sectional view of an articulating tissue cuttingdevice having a radiofrequency wire tissue cutter, according to oneembodiment of the present invention.

FIGS. 244A-244D are cross-sectional views of a portion of a spine andback, demonstrating a percutaneous method for removing ligamentum flavumtissue to treat spinal stenosis and/or neural/neurovascular impingement,according to one embodiment of the present invention;

FIGS. 245A and 245B are top and cross-sectional views, respectively, ofa device for removing ligamentum flavum tissue to treat spinal stenosisand/or neural/neurovascular impingement, according to one embodiment ofthe present invention;

FIGS. 246A-246E are cross-sectional views of a distal portion of adevice for removing ligamentum flavum tissue to treat spinal stenosisand/or neural/neurovascular impingement, according to one embodiment ofthe present invention;

FIGS. 247A-247E are cross-sectional views of a distal portion of adevice for removing ligamentum flavum tissue to treat spinal stenosisand/or neural/neurovascular impingement, according to an alternativeembodiment of the present invention;

FIGS. 247F and 247G are side and cross-sectional views of the portion ofthe device from FIGS. 247A-247E;

FIGS. 248A-248E are cross-sectional views of a distal portion of adevice for removing ligamentum flavum tissue to treat spinal stenosisand/or neural/neurovascular impingement, according to an alternativeembodiment of the present invention;

FIG. 249 is a perspective view of a distal portion of a poweredmechanical device for removing ligamentum flavum tissue to treat spinalstenosis and/or neural/neurovascular impingement, according to oneembodiment of the present invention;

FIG. 250 is a perspective view of a distal portion of a poweredmechanical device for removing ligamentum flavum tissue to treat spinalstenosis and/or neural/neurovascular impingement, according to analternative embodiment of the present invention;

FIGS. 251A-251B are top and side views, respectively, of a distalportion of a powered mechanical device for removing ligamentum flavumtissue to treat spinal stenosis and/or neural/neurovascular impingement,according to an alternative embodiment of the present invention;

FIG. 252 is a cross-sectional view of a portion of a spine and back anda flexible tissue modification device in place for removing ligamentumflavum tissue, according to one embodiment of the present invention;

FIG. 253 is a cross-sectional view of a portion of a spine and back andan articulating tissue modification device in place for removingligamentum flavum tissue, according to an alternative embodiment of thepresent invention;

FIG. 254A is a cross-sectional view of a portion of a spine and back anda flexible tissue modification device in place for removing ligamentumflavum tissue, according to an alternative embodiment of the presentinvention;

FIGS. 254B-254D are perspective views of portions of the device of FIG.254A, in greater magnification;

FIG. 255 is a cross-sectional view of a portion of a spine and back anda flexible, non-powered mechanical tissue modification device in placefor removing ligamentum flavum tissue, according to one embodiment ofthe present invention;

FIG. 256 is a cross-sectional view of a portion of a spine and back anda flexible tissue access device in place, with multiple optional tissueremoval tools for removing ligamentum flavum tissue, according to analternative embodiment of the present invention;

FIGS. 257A-257E are perspective and cross-sectional views of a tissuebarrier device and delivery device, according to one embodiment of thepresent invention;

FIGS. 258A and 258B are perspective views of a tissue barrier device,delivery device and tissue modification device, according to analternative embodiment of the present invention;

FIGS. 259A and 259B are perspective views of a tissue barrier device,delivery device and tissue modification device, according to analternative embodiment of the present invention;

FIG. 260 is a perspective view of a tissue barrier device, deliverydevice and tissue modification device, according to an alternativeembodiment of the present invention;

FIG. 261 is a perspective view of a tissue barrier device, deliverydevice and tissue modification device, according to an alternativeembodiment of the present invention;

FIG. 262 is a cross-sectional view of a tissue barrier device, accordingto one embodiment of the present invention;

FIG. 263 is a cross-sectional view of a tissue barrier device, accordingto an alternative embodiment of the present invention;

FIG. 264 is a cross-sectional view of a spine with a ligamentum flavumretracting device in place, according to one embodiment of the presentinvention;

FIG. 265 is a cross-sectional view of a spine with a ligamentum flavumretracting device in place, according to an alternative embodiment ofthe present invention;

FIGS. 266A-266P are cross-sectional views of a portion of a spine andback, demonstrating a percutaneous method for removing ligamentum flavumtissue, according to one embodiment of the present invention;

FIGS. 267A-267C are cross-sectional and perspective views of a tissuebarrier and needlette tissue removal device, according to one embodimentof the present invention;

FIG. 268A is a perspective view of a tissue barrier and needlette tissueremoval device, according to an alternative embodiment of the presentinvention; and

FIG. 268B is a perspective view of a tissue barrier and needlette tissueremoval device, according to an alternative embodiment of the presentinvention.

FIG. 269 is a side view of a portion of a lumbar spine without nerveroot impingement, showing two adjacent vertebrae, an intervertebraldisk, and a nerve root exiting an intervertebral foramen.

FIG. 270 is a side view of a portion of a lumbar spine as in FIG. 269,but demonstrating impingement of the nerve root by various tissues as ina case of spinal stenosis.

FIG. 271 is a cross-sectional view of a portion of a spine and back,with a tissue removal device in position for removing ligamentum flavumand/or bone tissue to treat spinal stenosis and/or neural/neurovascularimpingement.

FIG. 272 is a side view of a portion of a lumbar spine as in FIG. 269,with a device for measuring a foramen shown in cross-section.

FIG. 273 is a side view of a lumbar spine and device as in FIG. 272, butdemonstrating impingement of the nerve root by various tissues as in acase of spinal stenosis.

FIG. 274A is a perspective view of a device for measuring the compliantregion adjacent to a nerve root (e.g., in an intervertebral foramen),according to one embodiment of the present invention.

FIG. 274B is a cross-sectional view of a spine, showing the device ofFIG. 274A in place for measuring space in a foramen.

FIG. 275 is a side view of a system for measuring the compliant regionadjacent to a nerve root including multiple sound devices, according toone embodiment.

FIG. 276 is a side view of a device for measuring the compliant regionadjacent to a nerve root (e.g., a foramen) including multiple slideablesounds, according to one embodiment.

FIG. 277 is a side view of a tapered, dilation device for measuring anintervertebral foramen, according to one embodiment.

FIG. 278 is a side view of a tapered, expanding device for measuring anintervertebral foramen.

FIG. 279A is a cross-sectional view of a spine with an intervertebralmeasurement device.

FIG. 279B is a side view of a portion of a spine, showing an inflatableballoon portion of the device of FIG. 279A in cross section within anintervertebral foramen.

FIG. 280 is a side view of a proximal/distal balloon-type device formeasuring an intervertebral foramen.

FIG. 281A is a side view of a balloon-type device for measuring anintervertebral foramen including internal electrodes.

FIG. 281B is another variation of a balloon-type device for measuringintervertebral foramen,

FIG. 281C is a side view of another variation of a balloon-type devicewith a built-in miniature camera for measuring an intervertebralforamen.

FIGS. 282A and 282B are side views of a measurement device having anexpandable mesh portion.

FIG. 283 is a side view of a measurement device having an expandablepouch and multiple elongate expansion members.

FIG. 284 is a perspective view of a distal portion of a tissue removaldevice having an expandable portion for helping measure the compliantregion adjacent to a nerve root.

FIG. 285 is a perspective view of a distal portion of a tissue removaldevice having an expandable portion for helping measure the compliantregion adjacent to a nerve root.

FIG. 286 is a perspective view of a distal portion of a tissue removaldevice having an expandable portion for helping measure the compliantregion adjacent to a nerve root.

FIG. 287A is another variation of a device for measuring the compliantregion adjacent to a nerve root (e.g., in an intervertebral foramen)including a plurality of tight bipole pairs.

FIGS. 287B and 287C show enlarged views of the top and bottom(respectively) of the distal end of the device of FIG. 287A.

FIG. 288 illustrates the component parts of one exemplary system formeasuring.

FIG. 289 illustrates operation of one variation of a device formeasuring.

FIGS. 290A and 290B further illustrate the method of operation shown inFIG. 289.

FIGS. 291A to 291C illustrate another variation of a measurement device.

FIG. 292 is a cross-sectional view of portion of a spine and back,showing a tissue locking spinal access system in place.

FIG. 293 is a perspective view of a tissue locking spinal access system.

FIGS. 294A-294H are cross-sectional views of a portion of a spine andback, demonstrating a method for accessing a spine with a tissue lockingspinal access system.

FIGS. 295A-295G are cross-sectional views of a portion of a spine andback, demonstrating a method for accessing a spine with a tissue lockingspinal access system.

FIG. 296 is a posterior view of two adjacent lumbar vertebrae and anintervertebral disc, showing one example of a location for placing aspinal access cannula on vertebral bone.

FIG. 297 is a sagittal view of a portion of a lumbar spine, with atissue locking spinal access system in place and extending through theepidural space and between adjacent intervertebral spaces.

FIGS. 298A and 298B are side views of a telescoping, tissue lockingcannula system for spinal access.

FIG. 299 is a perspective view of a tissue locking spinal access system.

FIG. 300 is a perspective view of a tissue locking spinal access system.

FIG. 301 is a perspective view of an expanding, tissue locking spinalaccess cannula.

FIGS. 302A and 302B are side and perspective views of a curvedprobe/guide member system for accessing a spine through a minimallyinvasive cannula.

FIGS. 303A-303H illustrate the operation of one variation of aligamentum flavum access tool, configured as a punch tool.

FIG. 303J shows different variations of ligamentum flavum access toolsthat are configured as punch tools.

FIG. 303K is another variation of a ligamentum flavum access tool.

FIGS. 304A-304G illustrate operation of another variation of aligamentum flavum access tool, configured as an expander.

FIGS. 305A-305E illustrate operation of another variation of aligamentum flavum access tool.

FIGS. 306A-306D illustrate operation of another variation of aligamentum flavum access tool.

FIG. 306E shows different variations of ligamentum flavum access toolsthat are configured as barb-type tools.

FIGS. 307A-307D illustrate operation of another variation of aligamentum flavum access tool.

FIGS. 308A and 308B show additional steps that may be performed with aligamentum flavum access tool, such as the tool sown in FIGS. 307A-307D.

FIG. 309A shows an example of a generic device including an elongatebody and a bipole pair.

FIGS. 309B and 309C show a tight bipole pair.

FIGS. 309D-309F show bipole networks.

FIGS. 310A-310D are various views of portions of a neurostimulationdevice, according to one embodiment of the present invention.

FIG. 311 is cross-section through a device showing four circumferentialregions.

FIG. 312 is another cross-section through a device having fourcircumferential regions.

FIGS. 313A and 313B illustrate side views and cross-sectional views,respectively, of one variation of a portion of a nerve localizationdevice.

FIGS. 314A and 314B illustrate side views and cross-sectional views,respectively, of another variation of a portion of a nerve localizationdevice.

FIGS. 315A and 315B illustrate side views and cross-sectional views,respectively, of another variation of a portion of a nerve localizationdevice.

FIG. 316 is a side view of a nerve localization device showing multiplecurrent path direction features.

FIG. 317 is a circuit diagram of one variation of a portion of a nervelocalization device.

FIG. 318 is a perspective view of a portion of a nerve localizationdevice having two electrodes with rotating brushes.

FIGS. 319A-319C are simplified diagrams of one variation of a nervelocalization device.

FIG. 319D is a partial, simplified diagram of a rongeur tip configuredas a nerve localization device.

FIGS. 320A-320C illustrate elongate bodies having a plurality of regionseach including at least one bipole pair.

FIGS. 321A-321D show partial cross-sections through various deviceshaving elongate bodies including multiple regions.

FIGS. 322A-322B illustrate one variations of a device employed intissue.

FIG. 322C illustrates another variation of a device in tissue.

FIGS. 322D and 322E show a cross-section and a partial perspective view,respectively, of a device having an elongate body including fourregions.

FIG. 322F show a schematic illustration of an electrode that may formpart of a tight bipole pair.

FIG. 323 is a cross-section through another variation of a device.

FIGS. 324A-324D illustrate exemplary signals that may be applied to oneor more bipole pairs or networks within a region of a device.

FIG. 325A illustrates a system for determining if a nerve is nearbyapplied to a patient.

FIG. 325B-325D are simplified diagrams of sensors which may be used aspart of a system for determining if a nerve is nearby.

FIGS. 326A-326B illustrate variations of a device for determining if anerve is nearby.

FIGS. 327A-327C are flow diagrams illustrating method of determining ifa nerve is nearby a region of a device.

FIG. 328 is a block diagram illustrating components that may be part ofa system for determining if a nerve is nearby a device.

FIG. 329 is a cross-sectional view of a spine, showing a top view of alumbar vertebra, a cross-sectional view of the cauda equina, and twoexiting nerve roots.

FIG. 330 is a side view of a lumbar spine.

FIG. 331 is a cross-sectional view of a spine, illustrating a minimallyinvasive spinal decompression device and method including the use ofneural localization as described herein.

FIG. 332 is a block diagram of one variation of a nerve tissuelocalization system.

FIG. 333 is a perspective view of a nerve tissue localization system.

FIGS. 334A-334F are cross-sectional views of a spine, illustrating onemethod for using a nerve tissue localization system.

FIGS. 335A-335H are cross-sectional views of a spine, illustratinganother method for using a nerve tissue localization system.

FIGS. 336A and 336B show variations of devices for determining if anerve is nearby.

FIGS. 337A-337C show one variation of a rongeur including a tight bipolenetwork capable of determining if a nerve is in the cutting region ofthe rongeur.

FIGS. 337D and 337E illustrate other variations of a rongeur including atight bipole network.

FIG. 338 is a schematic illustrating an accelerometer-based system fordetermining if a nerve is nearby a neurostimulation electrode.

FIG. 339 shows a median sagittal section of two lumbar vertebra andtheir ligaments.

FIGS. 340A-340F illustrate one variation of a system with tools forbimanual treatment of tissue; this variation includes: two variations ofa guidewire or pullwire positioning probe tool (340A and 340B), aflexible neural localization tool (340C), a tissue modification tool(340D), a removable guidewire handle (340E), and a guidewire (340F).

FIGS. 341A-341J show the components of one variation of an inner spinousdistraction access and decompression kit.

FIGS. 342A-342J illustrate one variation of inserting an IPD to distracta patient's spine; FIGS. 342K-342R illustrate a method of decompressinga region of the spine that has been distracted after insertion of theIPD.

FIG. 343 shows one example of a spinal cord stimulator system implantedinto a patient. This spinal cord stimulator system includes a lead andmay be used to treat pain.

FIG. 344 shows a schematic of one potential pathway for implanting anelectrical lead using the pullwire systems described herein; in thisexample the pullwire is inserted so that it extends above a pedicle.

FIG. 345 shows another pathway that may be used to position and/oranchor a stimulator lead.

FIG. 346 illustrates one variation of a lead that is adapted for pullinginto position using a pullwire.

FIG. 347A illustrates a facet joint 951005 including the superior andinferior surfaces

FIG. 347B shows another portion of a spine including a facet joint951011 that may be fused as described herein.

FIGS. 348A-348C illustrate variations of joint treatment devices. InFIG. 348A, the treatment device includes a front and a back articulatingsurface that can be drawn across the joint surfaces to roughen them;FIGS. 348B-348D show different cross-sections through joint treatmentdevices, and FIG. 348E illustrates another variation of a jointtreatment device. Any of these joint treatment devices may be facetjoint treatment devices.

FIG. 349A illustrates a cross-section through one variation of afacet-joint modifying device that includes two bone-sawing elements.

FIG. 349B illustrates a cross-section through one portion of the devicehaving a breakable spacer.

FIG. 349C shows a top view of one variation of a facet-joint modifyingdevice configured to perform a facetectomy.

FIG. 350A shows one variation of a tissue treatment device having asemi-rigid or stiff and curved shape with a tissue cutting (e.g.,serrated) edge on one or more sides. The device may be delivered in anuncurled (flexible) configuration, but may be curved into a more rigidform. Similarly FIG. 350B shows another variation of a semi-rigid curvedtissue treatment device.

FIG. 351A shows a cross-section though a portion of the spine,indicating the more dense cortical bone regions.

FIGS. 351B and 351C illustrate one variation of a PLIF-type procedurethat is made more effective using the pullwire techniques describedherein.

FIG. 352 is cross-sectional view of a spine, showing a top view of alumbar vertebra, a cross-sectional view of the cauda equina, and twoexiting nerve roots.

FIG. 353 is a left lateral view of the lumbar portion of a spine withsacrum and coccyx.

FIG. 354 is a left lateral view of a portion of the lumbar spine,showing only bone and ligament tissue and partially in cross section.

FIG. 355 is a cross-sectional view of a patient's back and spine with aside view of a guidewire and tissue modification system in place forperforming a tissue removal procedure.

FIGS. 356A-356I illustrate one variation of a method for advancing atissue modifying device into a patient's body using a guidewire deliverysystem.

FIG. 357 is a cross-sectional view of a patient's back and spine and aside view of a rasp device and guidewire system.

FIG. 358 is a cross-sectional view of a patient's back and spine and aside view of an ultrasound device and guidewire system.

FIG. 359A is a cross-sectional view of a patient's back and spine and aside view of a tissue access device with swappable tissue modificationdevices and a guidewire system.

FIGS. 359B-359M are side/perspective views of distal portions of anumber of different devices which may be placed through/used with atissue access device such as that shown in FIG. 359A.

FIG. 360 is a cross-sectional view of a patient's back and spine and aside view of a tissue access device with swappable tissue modificationdevices and a guidewire system.

FIG. 361 is a perspective view of a tissue access device coupled with aguidewire.

FIG. 362 is a perspective view of a tissue access device coupled with aguidewire.

FIG. 363 is a perspective view of a tissue access device coupled with aguidewire.

FIGS. 364A and 364C are perspective views, and FIGS. 364B and 364D aretop views, of a distal end of a tissue modification device withguidewire coupling member and a shaped guidewire.

FIGS. 365A and 365B are perspective views of a distal end of a tissuemodification device with guidewire coupling member and a shapedguidewire.

FIGS. 366A and 366C are perspective views of a guidewire coupling memberand a shaped guidewire, demonstrating a method for coupling the two.

FIGS. 366B and 366D are top views of the guidewire coupling member andshape guidewire of FIGS. 366A and 366C.

FIGS. 366E and 366F are different perspective views of the guidewirecoupling member of FIGS. 366A and 366C, without the shaped guidewire.

FIGS. 367A-367C are perspective, top and side views, respectively, of aguidewire coupling member.

FIGS. 367D and 367E are top views of the guidewire coupling member ofFIGS. 367A-367C and a shaped guidewire, demonstrating a method forcoupling the coupling member with a shaped guidewire.

FIGS. 368A and 368B are perspective views of a guidewire couplingmember.

FIGS. 368C and 368D are top views of the guidewire coupling member ofFIGS. 368A and 368B and a shaped guidewire, demonstrating a method forcoupling the coupling member with the guidewire.

FIGS. 369A and 369B are top views of a single-cam guidewire couplingmember.

FIG. 370 is a top view of a double-cam guidewire coupling member.

FIGS. 371A-371C are top views of a movable-piece guidewire couplingmember.

FIG. 372A is a perspective view, and FIGS. 372B and 372C are sidecross-sectional views, of a split-cone guidewire coupling member.

FIG. 373 is a top view of a flat anvil guidewire coupling member.

FIG. 374 is a top view of a corner pinch guidewire coupling member.

FIG. 375 is a top view of an eccentric cam guidewire coupling member.

FIGS. 376A and 376B are perspective views of a hooked guidewire andreceiving guidewire coupling member.

FIGS. 377A and 377B are perspective views of a ball-and-socket guidewireand guidewire coupling member.

FIGS. 378A and 378B are top and perspective views, respectively, of aspool trap guidewire coupling member.

FIGS. 379A and 379B are side views of a semicircular ribbon guidewirecoupling member with textured guidewire.

FIG. 380 is a side view of a folded ribbon guidewire coupling memberwith textured guidewire.

FIG. 381 is a side view of a ribbon guidewire coupling member.

FIG. 382 is a side view of a multi-point guidewire coupling member.

FIG. 383 is a side view of a rough-surface guidewire coupling member.

FIGS. 384A-384D are side views of proximal and distal ends of variousguidewires.

FIG. 385A is a perspective view of a drill-shaped distal end of aguidewire.

FIG. 385B is a side view of a guidewire as in FIG. 385A, being passedthrough a probe device.

FIGS. 386A and 386B are perspective and exploded views of a handle forgrasping a guidewire.

FIGS. 387A to 387C illustrate one method of exchanging a device using apositioned guidewire.

FIG. 388 shows a perspective view of one variation of an exchangesystem.

FIGS. 389A and 389B illustrate locking of the exchange system of FIG.388.

FIG. 389C is a cross-section through the system shown in FIG. 388,showing exemplary dimensions.

FIG. 390A is a perspective view of another variation of an exchangesystem.

FIGS. 390B and 390C illustrate locking of the exchange system of FIG.390A.

FIG. 390D is a cross-section through the system shown in FIG. 390A,showing exemplary dimensions.

FIG. 391A is a perspective view of another variation of an exchangesystem.

FIG. 391B illustrates locking of the exchange system of FIG. 391A.

FIG. 391C shows a perspective view of one of the coupling members shownin FIG. 391A.

FIG. 392A is perspective view of a locking exchange system.

FIGS. 392B and 392C are cross-sectional views illustrating the operationof the exchange system shown in FIG. 392A.

FIGS. 393A-393C illustrate another locking exchange system.

FIGS. 394A-394B illustrate an exchange system including a threadedcoupling region.

FIGS. 395A-395C illustrate operation of a locking exchange system.

FIG. 396A is a perspective view of an exchange system; FIG. 396B is across-section of the exchange system shown in FIG. 396A.

FIG. 396C shows one variation of a locking portion in a coupling memberof the exchange system shown in FIG. 396A.

DETAILED DESCRIPTION

Various embodiments of tissue modification devices and systems, as wellas methods for making and using same, are provided. Although much of thefollowing description and accompanying drawing figures generally focuseson surgical procedures in spine, in alternative embodiments, devices,systems and methods of the present invention may be used in any of anumber of other anatomical locations in a patient's body. For example,in some embodiments, flexible tissue modification devices of the presentinvention may be used in minimally invasive procedures in the shoulder,elbow, wrist, hand, hip, knee, foot, ankle, other joints, or otheranatomical locations in the body. Similarly, although some embodimentsmay be used to remove or otherwise modify ligamentum flavum and/or bonein a spine to treat spinal stenosis, in alternative embodiments, any ofa number of other tissues may be modified to treat any of a number ofother conditions. For example, in various embodiments, treated tissuesmay include but are not limited to ligament, tendon, bone, tumor, cyst,cartilage, scar, osteophyte, inflammatory tissue and the like.Non-target tissues may include neural tissue and/or neurovascular tissuein some embodiments or any of a number of other tissues and/orstructures in other embodiments. In one alternative embodiment, forexample, a flexible tissue modification device may be used to incise atransverse carpal ligament in a wrist while inhibiting damage to themedian nerve, to perform a minimally invasive carpal tunnel releaseprocedure. Thus, various embodiments described herein may be used tomodify any of a number of different tissues, in any of a number ofanatomical locations in the body, to treat any of a number of differentconditions.

Tissue Removal Devices and Methods

The present application refers to various concepts described in U.S.patent application Ser. No. 11/429,377, titled “Flexible Tissue Rasp,”filed May 4, 2006, now U.S. Pat. No. 8,048,080 which is herebyincorporated by reference in its entirety. The present application alsorefers to concepts described in PCT Patent Application Pub. No.PCT/US2005/037136, titled “Devices and Methods for Selective SurgicalRemoval of Tissue, filed Oct. 15, 2005, which is hereby incorporated byreference in its entirety.

The present invention relates generally to medical/surgical devices andmethods. More specifically, the present invention relates to flexibletissue modification devices and methods.

A significant number of surgical procedures involve modifying tissue ina patient's body, such as by removing, cutting, shaving, abrading,shrinking, ablating or otherwise modifying tissue. Minimally invasive(or “less invasive”) surgical procedures often involve modifying tissuethrough one or more small incisions or percutaneous access, and thus maybe more technically challenging procedures. Some of the challenges ofminimally invasive tissue modification procedures include working in asmaller operating field, working with smaller devices, and trying tooperate with reduced or even no direct visualization of the tissue (ortissues) being modified. For example, using arthroscopic surgicaltechniques for repairing joints such as the knee or the shoulder, it maybe quite challenging to modify certain tissues to achieve a desiredresult, due to the required small size of arthroscopic instruments, theconfined surgical space of the joint, lack of direct visualization ofthe surgical space, and the like. It may be particularly challenging insome surgical procedures, for example, to cut or contour bone orligamentous tissue with currently available minimally invasive tools andtechniques. For example, trying to shave a thin slice of bone off acurved bony surface, using a small-diameter tool in a confined spacewith little or no ability to see the surface being cut, as may berequired in some procedures, may be incredibly challenging or evenimpossible using currently available devices.

One area of surgery which would likely benefit from the development ofless invasive techniques is the treatment of spinal stenosis. Spinalstenosis occurs when nerve tissue and/or the blood vessels supplyingnerve tissue in the spine become impinged by one or more structurespressing against them, causing symptoms. The most common form of spinalstenosis occurs in the lower (or lumbar) spine and can cause severepain, numbness and/or loss of function in the lower back and/or one orboth lower limb.

FIG. 1 is a top view of a vertebra with the cauda equina (the bundle ofnerves that extends from the base of the spinal cord) shown in crosssection and two nerve roots branching from the cauda equina to exit thecentral spinal canal and extend through intervertebral foramina oneither side of the vertebra. Spinal stenosis can occur when the spinalcord, cauda equina and/or nerve root(s) are impinged by one or moretissues in the spine, such as buckled or thickened ligamentum flavum,hypertrophied facet joint (shown as superior articular processes in FIG.1), osteophytes (or “bone spurs”) on vertebrae, spondylolisthesis(sliding of one vertebra relative to an adjacent vertebra), facet jointsynovial cysts, and/or collapse, bulging or herniation of anintervertebral disc. Impingement of neural and/or neurovascular tissuein the spine by one or more of these tissues may cause pain, numbnessand/or loss of strength or mobility in one or both of a patient's lowerlimbs and/or of the patient's back.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% (or more) of adults aged 50 and older and is the mostfrequent reason cited for back surgery in patients aged 60 and older.Patients suffering from spinal stenosis are typically first treated withconservative approaches such as exercise therapy, analgesics,anti-inflammatory medications, and epidural steroid injections. Whenthese conservative treatment options fail and symptoms are severe, as isfrequently the case, surgery may be required to remove impinging tissueand decompress the impinged nerve tissue.

Lumbar spinal stenosis surgery involves first making an incision in theback and stripping muscles and supporting structures away from the spineto expose the posterior aspect of the vertebral column. Thickenedligamentum flavum is then exposed by complete or partial removal of thebony arch (lamina) covering the back of the spinal canal (laminectomy orlaminotomy). In addition, the surgery often includes partial or completefacetectomy (removal of all or part of one or more facet joints), toremove impinging ligamentum flavum or bone tissue. Spinal stenosissurgery is performed under general anesthesia, and patients are usuallyadmitted to the hospital for five to seven days after surgery, with fullrecovery from surgery requiring between six weeks and three months. Manypatients need extended therapy at a rehabilitation facility to regainenough mobility to live independently.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the affected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. Unfortunately, a surgical spine fusion results in a loss ofability to move the fused section of the back, diminishing the patient'srange of motion and causing stress on the discs and facet joints ofadjacent vertebral segments. Such stress on adjacent vertebrae oftenleads to further dysfunction of the spine, back pain, lower leg weaknessor pain, and/or other symptoms. Furthermore, using current surgicaltechniques, gaining sufficient access to the spine to perform alaminectomy, facetectomy and spinal fusion requires dissecting through awide incision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Thus, while laminectomy, facetectomy, and spinal fusion frequentlyimprove symptoms of neural and neurovascular impingement in the shortterm, these procedures are highly invasive, diminish spinal function,drastically disrupt normal anatomy, and increase long-term morbidityabove levels seen in untreated patients.

Therefore, it would be desirable to have less invasive methods anddevices for modifying target tissue in a spine to help ameliorate ortreat spinal stenosis, while inhibiting unwanted damage to non-targettissues. Ideally, such techniques and devices would reduce neural and/orneurovascular impingement without removing significant amounts ofvertebral bone, joint, or other spinal support structures, therebyavoiding the need for spinal fusion and, ideally, reducing the long-termmorbidity resulting from currently available surgical treatments. It mayalso be advantageous to have minimally invasive or less invasive tissuemodification devices capable of treating target tissues in parts of thebody other than the spine. At least some of these objectives will be metby the present invention.

With reference now to FIG. 2A, a tissue modification device 10 accordingto one embodiment may suitably include a proximal handle 20 coupled witha shaft 12 having a proximal, rigid portion 13 and a distal, flexibleportion 14 on which one or more tissue modifying members 16 may bedisposed. A guidewire coupler 18 may be formed in (or attached to)flexible portion 14 at or near its distal end, for coupling with aguidewire 22, which in turn may be coupled with a guidewire handle 24(or “distal handle”), which may include a tightening lever 25 fortightening handle 24 around guidewire 22.

Device 10 is shown percutaneously placed in position for performing atissue modification procedure in a patient's spine, with variousanatomical structures shown including a vertebra V, cauda equina CE,ligamentum flavum LF, nerve root NR, facet F, and intervertebral foramenIF. Various embodiments of device 10 may be used in the spine to removeligamentum flavum LF, facet bone F, bony growths, or some combinationthereof, to help decompress cauda equina CE and/or nerve root NR tissueand thus help treat spinal stenosis and/or neural or neurovascularimpingement. Although this use of device 10 will not be continuouslyrepeated for every embodiment below, any of the described embodimentsmay be used to remove ligamentum flavum alone, bone alone, or acombination of ligament and bone in the spine to treat neuralimpingement, neurovascular impingement and/or spinal stenosis.

In one embodiment of a method for modifying tissue using device 10, adistal end of 22 guidewire may be placed into the patient, along acurved path between target and non-target tissue, and out of thepatient. A distal portion of guidewire 22 may then be coupled withguidewire handle 24, such as by passing guidewire 22 through a centralbore in handle 24 and tightening handle 24 around guidewire 22 viatightening lever 25 or other tightening means. A proximal end ofguidewire 22 may then be coupled with coupling member 18 and used topull distal shaft portion 14 between target and non-target tissues. Insome embodiments, device 10 may be advanced into the patientpercutaneously, while in alternative embodiments, device 10 may beadvanced through a small incision or larger incision. Once advanced intothe patient, flexible distal shaft portion 14 may be advanced along acurved path between the target and non-target tissues, and in someinstances may be pulled at least partway into an intervertebral foramenIF of the spine.

Proximal handle 20 and guidewire handle 24 may be pulled (or“tensioned”—solid/single-tipped arrows) to urge tissue modifying members16 against the target tissue (in this case, ligamentum flavum LF).Generally, tissue modifying members 16 may be fixedly attached to (orformed in) one side or surface of distal portion 14, while an oppositeside or portion of distal portion 14 faces non-target tissue, such ascauda equina CE and/or nerve root NR. The opposite side of distalportion 14 will generally be atraumatic and/or include an atraumaticcover, coating (such as a sterile lubricant), shield (made out of Teflonfor example), barrier, tissue capture member or the like. Withtensioning force applied to device 10, handles 20, 24 may be used toreciprocate device 10 back and forth (solid/double-tipped arrows) tocause tissue modifying members 16 to cut, remove, shred or otherwisemodify the target tissue. In various embodiments, for example, targettissue may include only ligamentum flavum LF, only bone, or acombination of both.

Reciprocation and tensioning may be continued until a desired amount oftissue is removed. Removed target tissue, in some embodiments, may becollected, captured or trapped between tissue modifying members 16and/or in one or more tissue capture members or chambers (not shown).When a desired amount of target tissue has been removed, which may bedetermined, for example, by tactile feedback provided to the surgeon bydevice 10, by radiographic imaging, and/or by direct visualization (suchas in an open surgical case), guidewire 22 may be released from distalhandle 24, and device 10 may be removed from the patient's back. Ifdesired, device 10 may be passed into the patient's spine again foradditional tissue modification, and/or other devices may be passed intothe spine.

Additional details of various methods for inserting and using device 10are provided below. For further explanation of guidewire systems andmethods for inserting devices to remove or otherwise modify tissue,reference may also be made to U.S. patent application Ser. Nos.11/468,247 (now U.S. Pat. No. 7,857,813) and 11/468,252 (now PublicationNo. US-2008-0086034-A1), both titled “Tissue Access Guidewire System andMethod,” and both filed Aug. 29, 2006, the full disclosures of which arehereby incorporated by reference.

Referring now to FIG. 2B, in various embodiments, device 10 may be usedin parts of the body other than spine to remove target tissue TT whileavoiding harm to non-target tissue NTT. For example, target tissue TTmay include soft tissue adhering to bone, such as ligament and/orcartilage, and/or may include bone. Non-target tissue NTT may includeany nervous tissue, vascular tissue, an organ, or any other tissue thata surgeon may desire to leave unharmed by a surgical procedure. In oneembodiment, for example, device 10 may be used to perform a minimallyinvasive carpal tunnel release procedure by releasing the transversecarpal ligament without damaging the median nerve. In some embodiments,such a procedure may be performed percutaneously with or without anendoscope. In other embodiments, device 10 may be used to removecartilage and/or ligament from a knee or shoulder in a minimallyinvasive procedure. In yet another embodiment, device 10 may be used toperform a minimally invasive bunionectomy. Therefore, although thefollowing discussion focuses primarily on various uses of alternativeembodiments of device 10 in spine, any of a number of other anatomicalstructures may be operated upon in different embodiments.

Referring now to FIG. 2C, in an alternative embodiment, a tissuemodification device 10′ may suitably include a proximal handle 20′,including a squeeze actuator 21′ and coupled with a shaft 12′ having aproximal, rigid portion 13′ and a distal, flexible portion 14′. One ormore tissue modifying members 16′ may be moveably coupled with one sideof flexible portion 14′, and a guidewire coupler 18′ may be formed in(or attached to) flexible portion 14′ at or near its distal end, forcoupling with a guidewire 22′ and thus a distal handle 24′ with atightening lever 25′.

In this alternative embodiment, squeeze actuator 21′ may be coupled withmoveable tissue modifying members 16′ by any suitable means, such thatactuating actuator 21′ (double-headed, solid-tipped arrow) causes tissuemodifying members 16′ to reciprocate back and forth (double-headed,hollow-tipped arrow). In use, therefore, device 10′ as a whole may beheld relatively stationary, while tissue modifying members 16′ arereciprocated. Proximal handle 20′ and rigid proximal shaft portion 13′may be used to steer device 10′ relative to target tissue, and of coursedevice 10′ may be moved in and out of the patient and/or the targettissue, but it may also be possible to hold device 10′ relativelystationary while reciprocating tissue modifying members 16′. In variousembodiments, squeeze actuator 21′ may be replaced with any suitablemechanical actuator, such as a trigger, lever or the like.

With reference now to FIG. 2D, in another alternative embodiment, atissue modification device 10″ may be similar to the previous embodimentbut may include, instead of squeeze actuator 21′, a button actuator 21″and a powered drive mechanism within handle 20″. Pressing buttonactuator 21″ may activate tissue modifying members 16″ to reciprocateback and forth to modify tissue. In various alternative embodiments,button 21″ may be replaced with any suitable actuator, such as atrigger, switch, dial or the like.

With reference now to FIG. 3A, in some embodiments tissue modificationdevice 10 may be provided as a system (or “kit”), including the variouscomponents described above in reference to FIGS. 2A and 2B. In someembodiments, a tissue modification system 15 or kit may suitably includedevice 10 of FIGS. 2A and 2B, as well as one or more additional devicesor components. For example, multiple guidewires 22 may be provided aspart of system 15. In some embodiments, system 15 may also include oneor more guidewire passage probes 32, 34 and a curved, flexible guidemember 36. In one embodiment, for example, an ipsilateral access probe32 and a contralateral access probe 34 may be provided. Curved guidemember 36 is generally configured to pass through a lumen in each ofprobes 32, 34 and includes an inner lumen through which guidewire 22 maybe passed. Guide member 36 may further include one or more depth marks35 to indicate to a surgeon when guide member 36 has been passed acertain distance into probe 32, 34 and a stop 37 to limit passage ofguide member 36 farther into probe 32, 34. In an alternative embodiment(not shown), such as might be used in a completely percutaneousprocedure, probes 32, 34 may be replaced with an introducer needle, suchas but not limited to a 14 gauge Touhy epidural needle or other size ortype of epidural needle. In such an embodiment, guide member 36 may bedesigned to pass through the bore of the needle. For further descriptionof various probe and guide member devices, reference may be made to U.S.patent application Ser. Nos. 11/468,247 (now U.S. Pat. No. 7,857,813)and 11/468,252 (now Publication No. US-2008-0086034-A1). Furtherreference may be made to U.S. patent application Ser. Nos. 11/457,416,titled “Spinal Access and Neural Localization,” now U.S. Pat. No.7,578,819, and filed Jul. 13, 2006; and U.S. No. 60/823,594, titled“Surgical Probe and Method of Making,” and filed Aug. 25, 2006, the fulldisclosures of which are hereby incorporated by reference.

Guidewire 22 may be made of any suitable material, such as Nitinol orstainless steel, and may include a sharp distal tip 23, to facilitatepassage of guidewire 22 through tissue, and a proximal shaped end 27 forcoupling with guidewire coupler 18. Further details of various guidewire22 embodiments and distal handle 24 are provided, for example, in U.S.patent application Ser. Nos. 11/468,247 (now U.S. Pat. No. 7,857,813)and 11/468,252 (now Publication No. US-2008-0086034-A1), which werepreviously incorporated by reference.

FIGS. 3A and 3B show proximal handle 20 and shaft 12 in greater detailthan in previous figures. In the embodiment shown, four tissue modifyingmembers 16 are fixedly attached to one side of flexible distal shaftportion 14, each comprising grooved blades with bi-directional cuttingedges. In various alternative embodiments, any number of tissuemodifying members 16 may be included, such as from one to twenty tissuemodifying members 16. Furthermore, tissue modifying members 16 may haveany of a number of different configurations, some of which are describedbelow, such uni-directional blades, bi-directional blades, teeth, hooks,barbs, hooks, pieces of Gigli saw (or other wire saw), wires, meshes,woven material, knitted material, braided material, planes, graters,raised bumps, other abrasive surfaces, other abrasive materials,deliverable substances and/or the like.

In various embodiments, proximal shaft portion 13, distal shaft portion14, tissue modifying members 16 and guidewire coupler 18 may be made ofany suitable material (or materials), and may be made from one piece ofmaterial as a single extrusion or from separate pieces attachedtogether. For example, in many embodiments, all of shaft 12 andguidewire coupler 18 may be made from one piece of material, and tissuemodifying members 16 may be attached to distal shaft portion 14, such asby welding. In alternative embodiments, however, guidewire coupler 18may be a separate piece attached to distal shaft portion 14 and/ortissue modifying members 16 may be formed in (rather than attached to)distal shaft portion 14. In yet another embodiment, distal shaft portion14 may comprise a flat piece of material coupled with rigid proximalshaft portion 13, such as by welding. In some embodiments, shaft 12 maybe formed from one piece of material, and distal shaft portion 14 may beflattened to derive its shape and flexibility. In some embodiments, oneor more slits may be formed in distal shaft portion 14, to enhance itsflexibility. In some embodiments, proximal shaft portion 13 may have acylindrical shape. In some embodiments, proximal shaft portion 13,distal shaft portion 14, or both may be hollow. Alternatively, anyportion of shaft 12 may be solid in some embodiments, such as to giveproximal shaft portion 13 added rigidity.

In one embodiment, guidewire coupler 18 may include a slot 19, shaped toreceive and hold guidewire proximal shaped end 27. In variousembodiments, slot 19 may be located on the top surface of distal shaftportion 14, as shown, or on the bottom surface. For further descriptionof various embodiments of guidewire couplers, reference may be made toU.S. patent application Ser. Nos. 11/468,247 (now U.S. Pat. No.7,857,813) and 11/468,252 (now Publication No. US-2008-0086034-A1). Insome embodiments, an atraumatic cover 30 may be disposed over part ofdistal shaft portion 14, forming atraumatic edges 33 and an aperture 31through which tissue modifying members 16 protrude. Cover 30 may be madeof any suitable atraumatic material, such as any of a number ofdifferent polymers. In some embodiments, cover 30 may also serve tocollect cut tissue. Cover 30 may be made of any suitable material, suchas a polymer, examples of which are provided below. In some embodiments,cover 30 may be made from a porous or semi-permeable material and/or oneor multiple holes may be formed in cover 30 to allow fluid to passthrough cover 30, thus allowing a greater amount of solid material to bepacked into a tissue collection portion of cover 30.

FIG. 3B is a side view of device 10. Tissue modifying members 16 may beseen extending above atraumatic edges 33 of cover 30 and having cuttingedges facing both proximally and distally. In alternative embodiments,tissue modifying members 16 may have only uni-directional cutting edges,such as facing only proximally or only distally. In the embodimentshown, guidewire coupler 18 is formed as a loop at the distal end ofdistal shaft portion 14. Guidewire shaped end 27 may generally fit intoslot 19 (not visible in FIG. 3B) to reside within the loop of guidewirecoupler 18 during use. In other embodiments, guidewire coupler 18 maycomprise a separate piece attached to the top side or bottom side ofdistal shaft portion 14. Examples of such embodiments are describedfurther in U.S. patent application Ser. Nos. 11/468,247 (now U.S. Pat.No. 7,857,813) and 11/468,252 (now Publication No. US-2008-0086034-A1).

The various components of device 10, including proximal handle 20, shaft12, tissue modifying members 16, guidewire coupler 18, and cover 30, maybe fabricated from any suitable material or combination of materials.Suitable materials include, for example, metals, polymers, ceramics, orcomposites thereof. Suitable metals may include, but are not limited to,stainless steel (303, 304, 316, 316L), nickel-titanium alloy, tungstencarbide alloy, or cobalt-chromium alloy, for example, Elgiloy® (ElginSpecialty Metals, Elgin, Ill., USA), Conichrome® (Carpenter Technology,Reading, Pa., USA), or Phynox® (Imphy SA, Paris, France). Suitablepolymers include, but are not limited to, nylon, polyester, Dacron®,polyethylene, acetal, Delrin® (DuPont, Wilmington, Del.), polycarbonate,nylon, polyetheretherketone (PEEK), and polyetherketoneketone (PEKK).Ceramics may include, but are not limited to, aluminas, zirconias, andcarbides. In some embodiments, one or more portions of shaft 12, forexample, may be reinforced with carbon fiber, fiberglass or the like.

Referring now to FIGS. 4A-4E, one embodiment of a method for modifyingtissue using flexible tissue modification device 10 is demonstrated ingreater detail. In these figures, a patient's skin, target tissue TT andnon-target tissue NTT are shown diagrammatically, rather than asspecific structures. In one embodiment, the method of FIGS. 4A-4E may beemployed in the spine, to remove ligamentum flavum, bone or both, withdevice 10 passing through an intervertebral foramen between twovertebrae, as shown in FIG. 2A. In other embodiments, other tissue inother areas of the body may be removed.

As shown in FIG. 4A, guidewire 22 with sharp tip 23 and shaped end 27may be passed into the skin, between target and non-target tissue, andout of the skin. Methods for passing guidewire 22 are described further,for example, in U.S. patent application Ser. Nos. 11/457,416 (now U.S.Pat. No. 7,578,819), 11/468,247 (now U.S. Pat. No. 7,857,813) and11/468,252 (now Publication No. US-2008-0086034-A1), which werepreviously incorporated by reference. As described in those references,in various embodiments, guidewire 22 may be placed using a percutaneousmethod, such as with a needle, or using an open method, such as with aprobe. In some embodiments, localization of neural tissue, such as withnerve stimulation on a guidewire passing probe or guidewire passingguide member may be used, to confirm that guidewire 22 is passed betweentarget and non-target tissue.

In some embodiments where the method is performed in the spine, one ormore substances or devices may be placed into the epidural space of thespine before or after placing guidewire 22, to create additional spacebetween target tissues, such as ligamentum flavum, and non-targettissues, such as cauda equina and nerve root. Substances may include,for example, any of a number of fluids or gels, such as radiographiccontrast medium. Devices may include, for example, a barrier or shielddevice. Injection of substances into the epidural space to create asafety zone is described in U.S. patent application Ser. No. 11/193,557(Pub. No. 2006/0036211), titled “Spinal Ligament Modification Kit,”assigned to X-Sten, Inc., and filed Jul. 29, 2005, the full disclosureof which is hereby incorporated by reference. Various barrier devicesfor placement in the spine are described, for example, in U.S. patentapplication Ser. No. 11/405,859, titled “Tissue Modification BarrierDevices and Methods,” and filed Apr. 17, 2005, now Publication No.US-2007-0213734-A1, the full disclosure of which is hereby incorporatedby reference.

Referring to FIG. 4B, distal handle 24 may be passed over sharp tip 23and tightened around guidewire 22, such as by moving tightening lever25. Distal handle 24 may be coupled with guidewire 22 at this point inthe process or at a later point, according to various embodiments.

As shown in FIG. 4C, guidewire 22 may next be coupled with proximaldevice portion 11, by coupling shaped guidewire end 27 (not visible)with guidewire coupler 18. In the embodiment shown, for example,guidewire shaped end 27 may be placed into coupling member 18(hollow-tipped arrow).

Referring to FIG. 4D, distal handle 24 may then be pulled (hollow-tippedarrow) to pull device 10 into the patient and to thus position tissuemodifying members 16 in contact with target tissue TT. In someembodiments, such as when device 10 is used in a spinal procedure andpasses through an intervertebral foramen, a surgeon or other physicianuser may use tactile feedback of device 10 passing into the foramen,such as when coupling member 18 and/or tissue modifying members 16 passinto the foramen, to determine when tissue modifying members 16 arepositioned in a desired location relative to target tissue TT.Alternatively or additionally, a surgeon may confirm that a desiredplacement has been achieved by using radiographic imaging, such asfluoroscopy, direct visualization, such as in an open surgical case, ora combination of multiple methods.

In some embodiments in which device 10 is used in the spine to treatspinal stenosis and/or neural or neurovascular impingement, device 10may be passed into the patient and to a position for modifying tissuewithout removing any vertebral bone. More specifically, in someembodiments, device 10 may be advanced into the patient, through anintervertebral foramen, and out of the patient without removing bone.This is contrary to the majority of current surgical methods fortreating spinal stenosis, which typically include removal of at leastsome vertebral bone, such as performing a laminotomy or laminectomy, andwhich often remove significant amounts of vertebral lamina, spinousprocess, facet and/or pedicle bony tissue, simply to access the surgicalsite. In one embodiment, for example, device 10 may be advancedpercutaneously into the patient, used to remove ligamentum flavum only,and withdrawn from the patient, without removing any vertebral bone.

As shown in FIG. 4E, once tissue modifying members 16 are positioned asdesired, relative to target tissue TT, proximal handle 20 and guidewirehandle 24 may be pulled (hollow-tipped arrows) to urge tissue modifyingmembers 16 against target tissue TT (solid-tipped, single-headedarrows). While maintaining pulling/tensioning force, handles 20, 24 maybe used to reciprocate device 10 back and forth (solid-tipped,double-headed arrows) to remove target tissue TT. During a procedure,rigid proximal shaft portion 13 may be used to help steer device 10, ormore specifically flexible distal shaft portion 14, relative to thetarget TT. For example, rigid shaft portion 13 may be used to moveflexible portion 14 laterally or to pivot shaft 12 about an axis locatedalong flexible portion 14. In one embodiment, for example, rigid portion13 may be used to manipulate flexible portion 14 within anintervertebral foramen, such as by pivoting shaft 12 or moving flexibleportion 14 laterally in a caudal and/or cephalad direction, relative tothe patient. The rigidity of rigid proximal shaft portion 13 maygenerally facilitate such steering, as compared to a completely flexibledevice.

When a desired amount of tissue is removed, device 10 may be removedfrom the patient, such as by detaching guidewire handle 24 fromguidewire 22 and pulling proximal handle 20 to withdraw device 10 andguidewire 22 out of the patient. In some embodiments, device 10 or anadditional device may be reinserted into the patient and used in asecond location to remove additional tissue. For example, in a spinalstenosis treatment procedure, device 10 may be used to remove tissuefrom (and thus decompress) a first intervertebral foramen and then maybe removed and reinserted to remove tissue from a second foramen. Thisprocess may be repeated to remove tissue from any number of foramina. Inone embodiment, device 10 may include a guidewire lumen, so that aguidewire may be placed into a second foramen while device 10 is in theepidural space of the patient. Device 10 may then be removed along withthe first guidewire 22, attached to the second guidewire, and reinsertedinto the second foramen to remove tissue. In some embodiments, tissuemay be removed from device 10 before reinserting device 10 into thepatient to remove more tissue.

Referring now to FIGS. 5A-5C, a flexible distal portion 40 of a flexibletissue modification device is shown, in various views. In FIGS. 5A-5Cand 6-25, various alternative embodiments of a flexible distal portionof a tissue modification device are shown in a generally straightconfiguration. However, all embodiments shown are flexible and thus mayassume a curved configuration. The embodiments are shown in straightconfiguration for ease of illustration only.

In one embodiment, flexible distal portion 40 may include a substrate 42(or “flexible, distal shaft portion”), multiple tissue modifying members44 coupled with substrate 42, and an atraumatic cover 46 disposed oversubstrate 42 and forming an aperture 48 and atraumatic bumpers 49. FIG.5B is an end-on view of substrate 42 and one of cutting members 44,which includes multiple teeth 45. FIG. 5C is a side view of substrate 42and one of cutting members 44, showing that each cutting member 44 hastwo cutting edges 43 in this embodiment.

The embodiment of FIG. 5A includes three cutting members 44 comprisingblades with multiple teeth 45 with grooves between them. Cutting members44 in this and other embodiments may include any suitable material, suchas but not limited to stainless steel or any of the materials listedpreviously above. Any number of cutting members 44 may be used, such asfrom one to twenty cutting members in various embodiments. Cuttingmembers 44 may have any suitable height and may be spaced apart from oneanother at any suitable distances. In one embodiment, for example,cutting members 44 may have a height designed to protrude just slightlyabove the height of bumpers 49, so that cutting members 44 can cuttissue but do not protrude so high as to inhibit advancement orpositioning of device in the patient. In some embodiments, cuttingmembers 44 may be constructed as separate pieces and attached tosubstrate 42, such as by welding or gluing with adhesive. In someembodiments, cutting members 44 may be built by stacking layers ofmaterial to one another and attaching the stacks to form one piece.Cover 46 may be coupled with substrate using any known or later inventedmanufacturing technique, such as thermoforming, injection molding or thelike.

In various alternative embodiments of distal portion 40 of FIGS. 5A-5C,as well as in all embodiments described below and alternatives thereto,any number of cutting members 44 may be used, cutting members 44 may bemade of any suitable material, and cutting members may be disposed alongsubstrate 42 in any configuration, pattern or the like. Therefore,various alternative materials, numbers, patterns and the like of cuttingmembers 44 will not be listed repeatedly for each alternativeembodiment.

Referring now to FIG. 6, in another embodiment, a distal portion of aflexible tissue modification device 50 may include substrate 42 and awire saw 52 coupled with substrate 42, such as by welding. In FIG. 6, aswell as in subsequent FIGS. 7-22, only a portion of each deviceembodiment including substrate 42 and one or more cutting members isshown, to simplify the drawing figures and description. Any of theseembodiments may also include an atraumatic cover and/or other features,but for simplicity's sake, these features are not shown. Referring tothe embodiment of FIG. 6, wire saw 52 may comprise any wire sawcurrently known or later invented, such as a Gigli saw, and may beattached to substrate 42 in any suitable pattern or configuration, suchas in an S-shape pattern, as shown, or a zig-zag, straight-line or otherpattern.

With reference to FIG. 7, in an alternative embodiment, a distal portionof a flexible tissue modification device 54 may include multiple piecesof wire saw 56 coupled with substrate 42. Again, these pieces of saw 56may be attached in any pattern and by any means, such as by welding, andmay comprise Gigli saw or other types of wire saw.

FIG. 8 shows a portion of another alternative embodiment of a flexibletissue modification device 58, in which abrasive materials 60, 62 areadhered to a surface of substrate. In some embodiments, only one typeand/or grain of abrasive material 60 or 62 may be used, while otherembodiments may include multiple types of material, multiple grains ofmaterial, or both. For example, in the embodiment shown, a finer grainof material 60 may be disposed at either end of a portion of coarsergrain material 62. Such a variation in grains may provide varyingdegrees of tissue modification and/or the ability to remove greateramounts of tissue with a coarser grain 62 and provide a smootherfinished surface to the tissue with the finer grain 60. In variousembodiments, any abrasive materials 60, 62 may be used, and thematerials may be adhered to substrate 42 via any method, such asadhering with adhesive or the like. One embodiment, for example, mayinclude abrasive materials such as those described in U.S. patentapplication Ser. No. 10/277,776 (Pub. No. 2003/0225412), titled“Surgical Ribbon File,” and filed Oct. 21, 2002, the full disclosure ofwhich is hereby incorporated by reference. In another embodiment,substrate 42 may be treated in such a way as to have an abrasivesurface, such as by sand blasting.

Referring to FIG. 9, in another alternative embodiment, a flexibletissue modification device 64 may include multiple tissue modifyingmembers 66, each including multiple, curved teeth 68. Cutting members 66may be made of stainless steel or other material(s). In someembodiments, cutting members 66 may be configured to primarily cutand/or shred ligamentous tissue, such as ligamentum flavum.

Referring to FIG. 10, in another alternative embodiment, a flexibletissue modification device 70 may include one or more tissue modifyingmembers 72 coupled with a first major surface of a flexible substrate42. Each tissue modifying member 72 may include a base 73 disposedbetween two blades 74, with a bend between base 73 and each blade 74. Aswill be described in greater detail below, each blade 74 may have afirst end coupled with substrate 42 via base 73 and may extend to asecond, cantilevered end. In some embodiments, each blade 74 may besubstantially in-line (i.e., a side of blade 74 oriented at betweenabout 0 degrees and about 45 degrees relative to a longitudinal axis ofsubstrate 42) and may also be substantially vertical (i.e., a side ofblade 74 forms an angle with the plane of substrate 42 of between about45 degrees and about 90 degrees). Blades 74 may have any of a number ofshapes, heights, lengths and the like, a number of embodiments of whichwill be described below. For example, Blades 74 may be designed, in oneembodiment, specifically for cutting or slicing ligamentous tissue, suchas ligamentum flavum.

Referring to FIG. 11, in another alternative embodiment, a flexibletissue modification device 76 may include multiple, laterally offsettissue modifying members 78 disposed laterally across a first majorsurface of a substrate flexible portion 42. In one embodiment, forexample, each tissue modifying member 78 may include a base 79 with twosubstantially vertical blades 80 disposed at its opposite ends. Anysuitable number of tissue modifying members 78 may be used in a givenembodiment, such as but not limited to between two members 78 (fourblades 78) and eight members 78 (16 blades 78), in alternativeembodiments. Blades 80 may each have a triangular or “shark-tooth”shape, with two sharp cutting edges and a pointed cantilevered tip. Inalternative embodiments, any of a number of other blade configurationsmay be used, some of which are described in greater detail below. In oneembodiment, blades 80 may be designed specifically for cutting orslicing ligamentous tissue, such as ligamentum flavum. Alternatively, oradditionally, blades 80 may be configured to cut bone. In oneembodiment, each blade 80 may have a height approximately equal to orgreater than a thickness of a ligamentum flavum. Such a blade 80 may bepositioned in the spine to extend through ligamentum flavum and contactbone. When reciprocated, such a blade 80 may cut ligamentum flavum aloneor may cut ligamentum flavum tissue and then, when it is removed, mayalso cut bone. Such a blade height and configuration may facilitatelateral steering of device 76. Various alternative embodiments of tissuemodification devices having vertically oriented blades are described ingreater detail below.

Referring to FIG. 12, in another alternative embodiment, a flexibletissue modification device 82 may include multiple tissue modifyingmembers 84 formed as holes in substrate 42 with raised edges, such asare found on a cheese grater. The raised edges of cutting members 84 maybe sharp, to provide cutting. Any number of tissue modifying members 84may be included, they may have any desired size, and they may be formedon substrate in any pattern. In some embodiments, cut tissue may passthrough the holes of cutting members 84 and thus through substrate 42.In some embodiments, a tissue capture device or member may be coupledwith the back side of substrate 42 to collect cut tissue that passesthrough cutting members 84.

Referring to FIG. 13, in another alternative embodiment, a flexibletissue modification device 86 may include multiple tissue modifyingmembers 88 formed as upward-facing holes in substrate 42. The raisededges of cutting members 88 may be sharpened, to provide cutting. Anynumber of tissue modifying members 88 may be included. In someembodiments, cut tissue may pass through the holes of cutting members 88and thus through substrate 42. In some embodiments, a tissue capturedevice or member may be coupled with the back side of substrate tocollect cut tissue that passes through cutting members 88.

Referring to FIG. 14, in another alternative embodiment, a flexibletissue modification device 90 may include multiple tissue modifyingmembers 92 formed as raised flaps in substrate 42, with each flap 92including a sharpened cutting edge 94. Any number of tissue modifyingmembers 92 may be included. In some embodiments, cut tissue may passunderneath the flap-like cutting members 92 and thus through substrate42. In some embodiments, a tissue capture device or member may becoupled with the back side of substrate to collect cut tissue thatpasses through cutting members 92.

Referring to FIG. 15, in another alternative embodiment, a flexibletissue modification device 96 may include multiple tissue modifyingmembers 98 formed as rounded cutting devices coupled with substrate 42.In one embodiment, each cutting member 98 may include multiple ridges,divided by grooves. In one embodiment, cutting members 98 may have aspiral or screw-like configuration.

Referring to FIG. 16, in another alternative embodiment, a flexibletissue modification device 102 may include multiple tissue modifyingmembers 104 comprising thin, flap-like blades coupled with substrate 42,each cutting member 104 including a sharp blade edge 106. Any number,size and configuration of blades may be used.

Referring to FIG. 17, in another alternative embodiment, a flexibletissue modification device 108 may include multiple different types oftissue modifying members 110, 111. For example, one embodiment mayinclude one or more jagged tissue cutters 110 each having multiple,triangular, raised teeth 112, and one or more bladed tissue cutters 111,each having multiple blades 113. Teeth 112 and/or blades 113 may beconfigured specifically to cut ligamentum flavum tissue, bone, or both,in various embodiments.

Referring to FIG. 18, in another alternative embodiment, a flexibletissue modification device 114 may include substrate 42, a tissueengaging member 116 including multiple barbs 117 (or hooks, needles orthe like), and one or more tissue cutting members 118, such as a raisedblade. In various embodiments, tissue engaging member 116 may beconfigured to hook, snag, grab or otherwise engage soft tissue, such asligamentum flavum, and pull or stretch such tissue as it is pulled orpushed across the tissue. Tissue cutting member 118 may follow behindtissue engaging member 116 and cut the stretched/pulled tissue. Suchstretching or pulling of tissue before cutting may facilitate or enhancetissue cutting.

Referring to FIG. 19, in another alternative embodiment, a flexibletissue modification device 122 may include a wire mesh 124 coupled withmultiple supporting structures 126 and an atraumatic material 128 on oneside. All components may be made of any suitable material, such as thoselisted previously.

Referring to FIG. 20, in another alternative embodiment, a flexibletissue modification device 130 may comprise a hollow, flattened shaft132, having central chamber or lumen 134, into which multiple grooves136 may be cut. An edge of each groove 136 may be raised and sharpenedto form a blade edge 138, thus forming a multiple, bladed tissuemodifying members. Tissue cut by blades 138 may pass under blades 138 tocollect within lumen 134 and may thus be transported out of the patient.

Referring to FIG. 21, in another alternative embodiment, a flexibletissue modification device 140 may include multiple tissue modifyingmembers 142 formed as holes in substrate 42 with raised edges, such asare found on a cheese grater. The raised edges of cutting members 142may be sharpened, to provide cutting. Any number of tissue modifyingmembers 142 may be included. In some embodiments, cut tissue may passthrough the holes of cutting members 142 and thus through substrate 42.In some embodiments, a tissue collection member 144, forming a tissuecollection chamber 148, may be coupled with the back side of substrate42 to collect cut tissue that passes through cutting members 142. Tissuecollection member 144 may also serve as an atraumatic tissue protectionmember and may include, for example, side bumpers 146 to avoid damagingnon-target tissue with sharp edges of device 140. In some embodiments,tissue collection member 144 may be strengthened by multiple fibers 145,such as wires or carbon fibers.

Referring to FIG. 22, in another alternative embodiment, a flexibletissue modification device 150 may include multiple sections 152 linkedtogether via linkages 154 to form a flexible device configurationanalogous to that of some watch bands. A tissue modifying member 156having a cutting edge 158 may be disposed on one side of each section152 to cut tissue.

Referring to FIG. 23, in another alternative embodiment, a flexibletissue modification device 160 may include one curved tissue modifyingmember 162 having multiple ridges.

Referring to FIG. 24, in another alternative embodiment, a flexibletissue modification device 166 may include one curved tissue modifyingmember 168 and multiple apertures 170 in substrate 42, each apertureopening into a tissue collection chamber 172 in substrate.

Referring to FIGS. 25A and 25B, in another alternative embodiment, aflexible tissue modification device 174 may include multiple, raisedtissue modifying members 176, each disposed on substrate 42 adjacent anaperture 178, through which cut tissue may pass into a tissue collectionchamber.

In various embodiments, any given flexible tissue modification devicemay act on tissue in a number of different ways, such as by cutting,ablating, dissecting, repairing, reducing blood flow in, shrinking,shaving, burring, biting, remodeling, biopsying, debriding, lysing,debulking, sanding, filing, planing, heating, cooling, vaporizing,delivering a drug to, and/or retracting target tissue. For example, manyof the devices described above may also optionally be loaded with adrug, bone wax, gel foam, or the like, which may be deposited during atissue modification procedure. Any suitable drug may be delivered viathe devices in various embodiments, such as but not limited to thrombin,NSAID, local anesthetic or opioid. In some embodiments, devices may alsodeliver an implant, such as a stent-like implant for maintaining patencyof decompressed intervertebral foramen, a rivet, staple or similardevice for retracting ligamentum flavum tissue, a tissue dressing, orthe like. In some embodiments, devices may cool or freeze tissue foranalgesia or to change the tissue's modulus of elasticity to facilitatetissue modification. Some embodiments of devices may also include avisualization and/or diagnostic component, such as an ultrasound, MRI,reflectance spectroscopy, fiber optic, endoscope, charge-coupled device(CCD), complementary metal-oxide semiconductor (CMOS) or other device.

Any of the devices described herein may also optionally include one ormore components for neural identification and/or localization. Forexample, in some embodiments, a flexible tissue modification device mayinclude one or more nerve stimulation electrodes on a backside orunderside of the device (i.e., a side designed to be atraumatic and facenon-target tissue). The electrode(s) may be used to confirm that theatraumatic side of the device is in contact with non-target neuraltissue, thus also confirming that the tissue modification members of thedevice are facing target tissue. In some embodiments, the devices mayalso include one or more electrodes on an upper surface, at or near thetissue modification members, to further confirm a desired placement ofthe device. For further description of such neural localization devicesand methods, reference may be made to U.S. Pat. No. 7,578,819, which waspreviously incorporated by reference.

In various alternative embodiments, any of the tissue modificationdevices and method described above may be used in combination with oneor more vertebral distraction devices. In one embodiment, for example,an interspinous implant such as the X STOP™ implant (offered by St.Francis Medical Technologies, Inc., Alameda, Calif., www.sfmt.com) maybe inserted between adjacent vertebrae, and then access devices and/ortissue removal devices described herein may be used to remove orotherwise modify spinal tissue. Such an implant may be inserted and leftin place after a procedure, while in alternative embodiments adistraction device may be used only during a tissue removal procedure.Various embodiments and aspects of such distraction/tissue removalcombinations are described in greater detail in U.S. Provisional PatentApplication Ser. No. 60/884,371, titled “Spinal Stenosis TreatmentMethods and Apparatus,” filed Jan. 10, 2007, the full disclosure ofwhich is hereby incorporated by reference. With reference now to FIGS.26A-26C, one embodiment of a flexible tissue modification device 180 andmethod for using it to remove tissue are demonstrated. As withpreviously described embodiments, device 180 may be used in an epiduralspace and intervertebral foramen of a spine to treat spinal stenosis butis shown in FIGS. 26A-26C in diagrammatic form, acting on a genericpiece of tissue. In the embodiment shown, tissue modification deviceincludes a rigid proximal shaft portion 182 and a flexible distal shaftportion, the latter of which may be coupled with a guidewire 192 duringuse. Flexible distal shaft portion 184 may include a lower substrate 186and an upper substrate 188, with a tissue collection space formedbetween the two and with multiple tissue modifying members 190 beingcoupled with the lower substrate 186 so as to extend through one or moreapertures in upper substrate 188. Device 180 may be tensioned(hollow-tipped arrows) and reciprocated (FIGS. 26B and 26C, solid-tippedarrows) to move cutting members 190 back and forth across tissue andthus remove the tissue.

In one embodiment, as tissue is removed 196, it may pass through theaperture(s) in upper substrate 188 and become trapped in tissuecollection area 189 between substrates 186, 188. As device 180 isreciprocated back and forth under tension, trapped tissue 196 may besqueezed between substrates to move farther and farther away fromcutting members 190, thus allowing for more cut tissue 196 to be passedinto and moved through collection area 189. In some embodiments, device180 may further include side enclosures disposed between upper substrate188 and lower substrate 186 to prevent cut tissue 196 from exiting outthe sides of collection area 189. Upper substrate 188 may also helpprotect non-target tissues from harm, such as lateral vessels supplyinga facet joint with blood supply.

FIGS. 27A-27C illustrate another embodiment of a two-substrate, flexibletissue modification device, similar to that described in reference toFIGS. 26A-26C. FIG. 27A demonstrates a method of making a device 200 bycoupling an upper substrate 204 to a lower substrate 202 while the twoare wrapped around a round structure, such as a dowel rod 203. Bywrapping substrates 202, 204 around a dowel and then attaching them toone another at attachment points, upper substrate 204 will have asmaller radius of curvature than lower substrate 202. As is seen inFIGS. 27B and 27C, when device 200 is then straightened, lower substrate202 bows outward relative to upper substrate 204, thus forming a space212 for tissue collection between the two. Additionally, when tissuemodifying members 206 are attached to the top side of lower substrate202, upper substrate 204 will rise above the tops of cutting members 206when device 200 is held in a straight configuration, but cutting members206 will protrude through one or more apertures 210 in upper substrate204 when device 200 is held in a curved configuration. In variousembodiments, substrates 202, 204 may be coupled together at attachmentlines 208, which may be located at any desired distance from cuttingmembers 206.

Referring now to FIGS. 28A and 28B, another alternative embodiment of adouble-substrate, flexible tissue modification device 214 is shown. Thisembodiment is much like the embodiment just described in reference toFIGS. 27A-27C, including an upper substrate 218 attached to a lowersubstrate 216 to form a tissue collection area 217 between the two. Thisembodiment include an additional feature, however, of multiple,uni-directional valves 220, which help to direct cut, collected tissueaway from tissue modifying members (not shown) of device 214. As shownin FIG. 28B, which shows a magnified portion of FIG. 28A, cut tissue 222may be trapped by valves, thus preventing it from moving toward themiddle portion of tissue collection chamber 217 and toward the tissuemodifying members.

FIG. 28C shows a portion of an alternative embodiment of a device,including an upper substrate 218′, a lower substrate 216′, a tissuecollection chamber 217′, and multiple one-leaf valves 220′ for trappingcut tissue 222′.

With reference now to FIG. 29A, in another embodiment, a flexibleportion of a tissue modification device 230 may include a shaft 232, asubstrate 234 disposed in shaft 232, an upper floating substrate 236disposed over substrate 234 and including an aperture 238, and multipletissue modifying members 240 disposed on substrate 234 and extendingthrough aperture 238.

FIGS. 29B and 29C are end-on views of a slightly varied embodiment, inwhich floating substrate 236 is shaped, and tissue modifying members 240are more raised. These figures demonstrate that floating substrate isfree to float downward, as in FIG. 29B, so that cutting members 240extend through aperture 238 to cut tissue, and is also free to floatupward, as in FIG. 29C, so that it covers tissue modifying members 240and prevents them from cutting tissue. As floating substrate 236 floatsupward, it is trapped by arms 233 of shaft 232. As tissue is cut bycutting members 240, it may pass through aperture 238 to reside in thespace between substrate 234 and floating substrate 236. As more cuttissue is cut and collected in the space, floating substrate 236 mayrise and cutting members 240 may be less and less exposed to cut tissue.Thus, floating substrate may help determine when a sufficient amount oftissue has been removed during a procedure.

Referring now to FIG. 30, in some embodiments, a flexible tissuemodification device 250 may include a hollow shaft 251, a proximal endof which may be coupled with a proximal handle (not shown) and a distalend of which may include a guidewire coupler 262. In one embodiment,shaft 251 may be formed from one piece of material, such as a hollowtube of stainless steel, and guidewire coupler 262 may also be formedfrom the same piece of material or, alternatively, may be a separatepiece welded to shaft 251. Shaft 251 may include a rigid proximal shaftportion 252 and a distal flexible shaft portion 254. In someembodiments, shaft 251 may have an approximately tubular shape at itsproximal portion 252 and may be flattened to form distal portion 254.Distal portion 254 may include multiple slits 256 to confer flexibilityor added flexibility. Distal portion 254 may also include multiplecutting members 260, formed by creating grooves 258 in distal portion254 and raising cutting edges at one side of each groove 258, as in theembodiment described in FIG. 20. In various embodiments, any number ofgrooves, 258, cutting members 260 and slits may be included. Differentembodiments may include different numbers of these features, forexample, depending on tissue to be cut, anatomical structures to beaccessed and the like.

In some embodiments, device 250 may include means for transportingremoved tissue through the device, either to facilitate storage of theremoved tissue in another part of the device, to transport the removedtissue out of the patient, or both. Other device embodiments may alsoinclude tissue transport means, such as the embodiments described inrelation to FIGS. 26-29, which include multiple substrates that formtissue collection chambers between the substrates. In some embodiments,two-substrate devices such as those in FIGS. 26-29 may be at leastpartially covered with material or attached at the sides, to form anenclosed tissue collection chamber between the substrates. In otherembodiments, tissue may be moved between the two substrates even thoughthe tissue collection area is not fully enclosed. In any event, someembodiments of a flexible tissue modification device that include meansfor collecting tissue may also optionally include means for transportingthe tissue out of the device and, thus, out of the patient. In someembodiments, cut tissue may simply be collected in one or more tissuecollection chambers or storage areas and then may be removed from thepatient by removing the device from the patient. In other embodiments,however, tissue transport means may be used to move tissue out of thepatient through a tissue modification device without removing the devicefrom the patient. Several embodiments of such tissue transport meanswill now be described.

Referring now to FIG. 31, in one embodiment, a flexible tissuemodification device 270 (shown diagrammatically in side cross-section)may include a hollow shaft 272, forming an inner tissue collection lumen(or “chamber”) 278. Grooves 274 may be formed in a surface of shaft 272,and tissue modifying members 276 may be formed between grooves 274. (Forease of illustration, cutting members 276 are shown in diagrammatic formand are not raised or sharpened, although in some embodiments one edgeof each cutting member 276 may be raised and sharpened.) In oneembodiment, tissue transport means may include an irrigation tube 280(or lumen) for introducing fluid into tissue collection lumen 278,suction (or “vacuum”) force may be applied to tissue collection lumen278 to suction fluid and cut tissue out through device 270. In analternative embodiment, a separate suction tube (or lumen) may beincluded (not shown). As tissue is cut by tissue modifying members 276,it may be directed into collection lumen 278 (solid-tipped arrows) viasuction force as well as by the force of circulating irrigation fluid.In various embodiments, any known suction device(s) may be coupled witha proximal end of device 270 to provide suction, and any knownirrigations device(s) may be coupled with irrigation tube 280 to provideirrigation. Irrigation tube 280 and collection lumen 278 may have anydesired diameter and be made of any suitable material(s).

With reference now to FIG. 284, in an alternative embodiment, a flexibletissue modification device 284 may include a hollow shaft 286 includingmultiple grooves 288 and tissue modifying members 290, and tissuetransport means including a moveable tissue collection compartment 292disposed within shaft 286, and a pull wire 294 to pull compartment 292out of device 284. As tissue is cut, at least some of it may fall into(or is directed by tissue modifying members 290 into) tissue collectioncompartment 292. Pull wire 294 may be used at any time to retractcompartment 292 proximally through device 284 to transport cut tissueout. In some embodiments, compartment 292 may be emptied of cut tissueand advanced back into shaft 286, such as by using pull wire 294 to pushit into shaft 286. In another embodiment, compartment 292 may be filledonly once during a procedure. Compartment 292 may have any desired size,shape and configuration, according to various embodiments, and may bemade of any suitable material.

In another alternative embodiment, and referring now to FIG. 33, aflexible tissue modification device 296 may include a hollow shaft 298including multiple grooves 300 and tissue modifying members 302, andtissue transport means including a flat piece of flexible material 304,having an outer, tissue-adhering surface 305 and being disposed over arotating dowel 306, such as in a conveyor belt configuration. As cuttissue enters or is directed into shaft 298 through grooves 300, it maystick to adhering surface 305 and thus be conveyed out of device 296proximally. In some embodiments, dowel 306 and/or a proximal dowel (notshown) may have a ratcheting mechanism, so that material 304 can onlymove in one direction. Any material, such as various flexible polymersand the like, may be used for making material 304 in variousembodiments.

Referring to FIG. 34A, in another embodiment, a flexible tissuemodification device 308 may include a hollow shaft 310 includingmultiple grooves 312 and tissue modifying members 314, and tissuetransport means including a retractable tissue adhering material 316. Aswith the above embodiment, any suitable material 316 may be used. Insome embodiments, material 316 may be retracted, cleaned and reinserted.In other embodiment, multiple pieces of material 316 may be used.

In some embodiments, as show in FIGS. 34B and 34C, a ratchetingmechanism 318 may be used to retract material 316. For example, material316 may include multiple apertures 318 or slits, which teeth ofratcheting mechanism 318 may used to pull material 316 out of device308.

With reference to FIG. 35, in another alternative embodiment, a flexibletissue modification device 320 may include a hollow shaft 322 includingmultiple grooves 324 and tissue modifying members 326, and tissuetransport means including multiple wires 328, each having a tissueadhering material 330 attached thereto or formed therein. For example,material 330 and wire 326 may be configured similar to a pipe cleaner.In another embodiment, material 330 may comprise multiple bends, hooksor other patterns bent into wires 326. In various embodiments, as few asone wire 328 or as many as twenty or more wires 326 may be preloadedinto device 320. Where multiple wires 328 are preloaded, they may bewithdrawn one by one during a procedure to remove tissue as it is cut.In some embodiments, one or more wires 328 may be inserted during aprocedure—i.e., new wires 328 may be inserted and/or used wires 328 maybe cleaned and reinserted. Any suitable size, shape, configuration,number and material(s) may be used, according to various embodiments.

FIG. 36A-36B show another variation of a tissue modification devicehaving a tissue collection region (pouch 3601). In this example, thetissue collection region is configured as a pouch that is formed betweenthe bottom (the back surface shown in FIG. 36A) and the top (the cuttingsurface shown in FIG. 36B). The bottom surface forming the pouch (theback surface of the device) may be formed of a flexible material. Inthis example, the back surface is formed of a flexible polymericmaterial such as PET. The cutting surface may be referred to as thefirst major surface in this example (FIG. 36A) and the back surface maybe referred to as the second major surface, which is the outer side ofthe pouch, shown in FIG. 36A. In FIGS. 36A and 36B, the first major(e.g., substantially flat) surface and the second major surfaces areattached to each other by stitching. For example, a Nitinol thread maybe used to stitch the material forming the second major surface to thematerial (metal) forming the first major surface. Alternatively, thesecond surface could be bonded to the first surface through adhesivesand/or heat processes used to fuse the two fuse the two surfaces. Also,the second surface could be tied to the first surface through aninjection molding process.

FIG. 36C shows another variation of a tissue modification deviceincluding a tissue collection region configured as a pouch. Thisexample, is very similar to the example shown in FIG. 36A, except thestitching used to secure the materials forming the first and secondmajor surfaces together are stitched differently. In some variations thetissue collection region is removable. For example, the material formingthe second major surface may be removable. In some examples, the tissuecollection region may be expandable.

FIGS. 37A and 37B illustrate another variation of a tissue modificationdevice in which the second major surface (the back surface in FIG. 37A)and the first major surface (the cutting surface in FIG. 37B) form atissue collection region between them. In this example, the second majorsurface is formed of a metallic material that is cut in multiple lines.The first and second major surfaces may fabricated from a single tubularelement. These parallel cuts form slats, and they may allow the metallicbottom region 3701 to be more flexible, while maintaining the separationof the tissue collection region, based on the relative rigidity of themetal 3701 forming the bottom surface. Thus, the tissue collectionregion formed between the bottom surface 3701 and the cutting surface3705 may be held open even when the device is in operation. In somevariations the tissue collection region includes a frame or structurethat helps to hold the tissue collection region open even when tensionis applied to drive the device against the tissue, in order to cut orotherwise modify the tissue.

Any of the tissue collection regions described herein may be configuredas static tissue collection regions. A static tissue collection regionallows storage of the collected tissue within the region, rather thanremoval from the device. For example, in some variations the tissuecollection region is a pouch (such as a removable pouch). During theprocedure, tissue cut by the device can be stored in the pouch (staticstorage). The tissue collection region can later be emptied, or theentire pouch can be disposed of.

Removable tissue collection regions (e.g., removable pouches) and tissuemodification devices including removable tissue collection regions areillustrated in FIGS. 38A-44C. For example, FIGS. 38A and 38B illustratethe operation of an expandable and removable tissue collection region.In this example, the removable pouch is formed by a flexible region 3805that is connected to two slideable tracks that are configured to matewith the upper (cutting) surface 3803, including blade 3801. As shown inFIG. 38B, during use the tissue collection pouch fills with material andexpands. The pouch may be removed (e.g., when sufficiently full) andemptied (for re-use) or disposed of. Similar variations are shown inFIGS. 39A-40B. For example, in FIG. 39A-39B, the cutting surface 3903(the first major surface) includes a track or guide region 3901 intowhich the expandable and removable second major surface 3901 slides toform the pouch region (tissue collection region) between the cuttingsurface and the removable surface. FIG. 39C illustrates a cross-sectionthrough just the removable surface. In this example, the expandablematerial forming the surface 3903 can be bonded to two parallel rods orwires that are secured in the track connected to the cutting surface.

FIGS. 40A and 40B show a similar expandable tissue collecting region inwhich the track or guide 4005 is attached to the second (expandable)surface. In this example, the second, expandable, surface is removable,but can slideably engage the upper (cutting 4001) surface. FIG. 40Cshows a perspective view of the lower surface.

FIGS. 41A and 41B show another variation of an expandable and removabletissue collection region formed between a first and second majorsurface, similar to the variation shown in FIGS. 38A and 38B. In thisexample, the lower surface (including the expandable member 4101)includes two tracks that can mate with the cutting surface, so that thetwo surfaces can slide together to form the tissue collection regiontherebetween. A pouch is formed between these two surfaces. The lowersurface may be secured to the upper surface by engaging locking tabs4103, 4105 between the two surfaces. Locking tabs may be any appropriateengagement region between the two surfaces. For example, the lockingtabs may be indentations on one or both surfaces that engage with aprojection on the opposite surface. FIG. 41B illustrates the device ofFIG. 41A during flexion. Bending the device may help secure the twosurfaces together. For example, bending the device may place the tablocks in tension and/or compression, helping to secure the cuttingsurface and the lower, expandable surface together. In this example, thelower surface slides onto the distal end of the cutting surface.

In some variations, the lower surface forming the tissue collectionregion is disposable, so that after use (e.g., after filling withtissue) it may be discarded and the cutting surface 4203 may be re-used.FIG. 42 illustrates one variation of a device having a disposable member4201. The disposable member in this example has two parallel surfaces.The first surface includes slots 4207 or passages which open into apouch formed between this first surface and a second expandable material4210. The disposable tissue collection region mates with the cuttingsurface 4103 through slots 4212 on the upper surface of the disposabletissue collection region. The disposable tissue collection region(pouch) may be secured to the cutting surface by lock tabs 4205, 4205′.

FIGS. 43-44C are other variations of removable (and possibly disposable)tissue collection pouches that mate with a (possibly reusable) cuttingsurface. For example, in FIG. 43, the disposable and removable pouchregion 4302 is configured to slide over the cutting surface 4304. Thecutting surface includes a plurality of debris ports 4301. When thewaste pouch 4302 is positioned and secured to the cutting surface 4304(e.g., by engaging lock tabs 4309, 4309′), these debris ports 4301 alignwith the slots opening into the tissue collection region 4311. In thisexample, the waste pouch may be slid over the distal end of the cuttingsurface.

FIG. 44A-44C illustrate another variation of a tissue modificationdevice in which the device is formed from at least 2 wires (need anumber), cutting surface and a mesh 4405 attached to the wires. Thecutting surface is actually multiple discrete cutting surfaces 4403 thatare connected to the two wires. The mesh is attached to the wires andforms a tissue collection region between the upper surface (holding thecutting surface(s) and the lower (protective) surface. In FIG. 44A threecutting surfaces are shown, and FIG. 44C shows an enlarged view of oneof the discrete cutting surfaces 4403. The cutting surface includesmultiple cutting surfaces or blades that project upward to a height, h,and the cutting surface is some minimum width, D, as shown in FIG. 44C.FIG. 44B shows a cross-section through the tissue modification deviceshown in FIG. 44A at the level of a cutting surface. Between the cuttingsurfaces, the upper surface of the device (the surface that will bedriven against the tissue) includes multiple openings or ports 4405 intothe tissue collection region. In some variations, the mesh or wires areformed at least partially of a shape memory material, such as a Nitinol.For example, the framework may be made of Nitinol wire. In somevariations, the mesh forming the device is at least partially made of anexpandable material. Thus, the tissue collection pouch may beexpandable. The mesh forming the device may be coated and/or impregnatedwith a lubricious material, such as a lubricious polymer, which willreduce friction when the device is drawn against the target tissue.

Any of the devices described herein may also optionally include one ormore components for neural identification and/or localization. Forexample, in some embodiments, a flexible tissue modification device mayinclude one or more nerve stimulation electrodes on a backside orunderside of the device (i.e., a side designed to be atraumatic and facenon-target tissue). The electrode(s) may be used to confirm that theatraumatic side of the device is in contact with non-target neuraltissue, thus also confirming that the tissue modification members of thedevice are facing target tissue. In some embodiments, the devices mayalso include one or more electrodes on an upper surface, at or near thetissue modification members, to further confirm a desired placement ofthe device. For further description of such neural localization devicesand methods, reference may be made to U.S. U.S. Pat. No. 7,578,819,which was previously incorporated by reference.

With reference now to FIG. 45, in another alternative embodiment, atissue modification device 160 may suitably include a proximal handle170 coupled with an elongate body 162 (or “shaft”) having a proximal,rigid shaft portion 163, a distal flexible portion 164 having a firstmajor surface 165 and an opposed second major surface 167, and multiplesubstantially in-line, substantially vertical blades 166 disposedlaterally across first major surface 165. Second major surface 167 maybe atraumatic, to inhibit injury to non-target tissues NTT. A guidewirecoupler 168 may be formed in (or attached to) flexible portion 164 at ornear its distal end, for coupling with a guidewire 172, which in turnmay be coupled with a guidewire handle 174 (or “distal handle”), whichmay include a tightening lever 175 for tightening handle 174 aroundguidewire 172. In one embodiment, device 160 may have many of thecharacteristics and be used in much the same way as embodimentsdescribed above, such as device 10 of FIG. 2A. The number, height,length, configuration and placement of blades 166, however, may conferunique tissue cutting/removal characteristics to device 160.

In FIG. 45, device 160 is shown passing into a patient, along a curvedpath between a generic soft tissue/bone combination and nearbynon-target tissue NTT, and back out of the patient. In one embodiment,device 160 may be passed into a patient, through an intervertebral spaceof the patient's spine (between ligamentum flavum andneural/neurovascular tissue), and back out of the patient, as describedin detail above with reference to alternative embodiments. Once device160 is in place for modifying a target tissue, such as soft tissueand/or bone, handles 170, 174 may be pulled (hollow-tipped arrows) toapply force and thus urge blades 166 into soft tissue (single-headed,solid-tipped arrows). Device 160 may then be reciprocated(double-headed, solid-tipped arrows), while maintaining some or all ofthe pulling force, to remove or otherwise modify the target soft tissueand/or bone. As mentioned previously, before reciprocating device 160 toremove tissue, in some embodiments the device may be used to stimulatenearby nerve tissue, such as with an electrode coupled with second majorsurface 167 and/or first major surface 167. Such nerve stimulation mayhelp confirm that device 160 has been placed in a desired location fortreatment and may be monitored using electromyography (EMG), visualobservation of muscle twitch and/or the like. Second major surface 167may be made atraumatic in a number of different ways, such as but notlimited to forming second major surface 167 with an atraumatic material,smoothing surface 167 during the manufacturing process, coupling anatraumatic cover with surface 167 and/or coating surface 167 with alubricious coating.

In various embodiments, device 160 may be optimized for removal of softtissue (such as ligamentum flavum or other ligamentous tissue), bone ora combination of both. Such optimization, for example, may be achievedwith various heights, lengths, edge types, numbers and/or placement ofblades 166. In some embodiments, it may be possible to remove both softtissue and bone with device 160, such as by continuing to reciprocatedevice 160 after soft tissue has been removed and/or by using differentamounts of pulling force to remove different types of tissue. Forexample, in one embodiment, if a surgeon only desires to remove softtissue, he/she may apply a first amount of pulling force. If, instead,the user desires to remove only bone tissue, it may be possible to applysufficient force to cut immediately through ligament and address bone.In other embodiments, a user may apply a first amount of tension todevice 160 to remove soft tissue and a second amount of tension toremove bone, within the same procedure. For example, it typicallyrequires approximately 30,000 psi of force to cut cortical bone. Thus,in embodiments where it is desired to cut bone, at least some of blades166 may have bone-cutting tips. In such an embodiment, first majorsurface 165, when bending over a bone surface, may have an active regionwith blades 166 that can be urged into soft tissue (such as ligament),and manual tension forces applied to device 160 divided by a combinedsurface area of the bone cutting tips of blades 166 within the activeregion may be at least 30,000 psi. In an alternative embodiment, atleast some of blades 16 may have bone-protecting ends, and manualtension forces applied to device 160 divided by a combined surface areaof the bone-protecting ends of blades 166 within the active region maybe less than 30,000 psi. Such an embodiment may facilitate removal ofsoft tissue, if blades 166 ride or “skate” over the bone and are thusfocused on soft tissue removal.

Referring to FIG. 46, in one embodiment a tissue modification device 180may include a proximal handle 189 coupled with one end of an elongatebody 182, which includes a proximal rigid shaft portion 183 and a distalflexible portion 184. Multiple substantially vertical, substantiallyin-line blades 186, 186′ may be disposed on a first major surface 185 offlexible portion 184, while a second major surface 187 approximatelyopposite first major surface 185 is substantially atraumatic to inhibitdamage to non-target tissues during a tissue modification procedure.(Again, by “substantially in-line,” it is meant that a side of eachblade is aligned at an angle of between about 0 degrees and about 45degrees relative to the longitudinal axis of the elongate body. By“substantially vertical,” it is meant that each blade forms an anglewith the first surface of the elongate body of between about 45 degreesand about 90 degrees.) Flexible portion 184 may also include a guidewirecoupler 188 at its distal end.

In various embodiments, a number of which are described further below,any suitable combination of blades 186, 186′ may be included on a giventissue modification device. For example, device 180 includes fourpointed-tip blades 186 and two flat-top blades 186′ of various heightsand lengths. Various blades may be configured to perform one or more ofa number of functions. For example, pointed-tip blades 186 may be idealfor removing bone, while flat-top blades 186′ may work best at removingsoft tissue and riding along a bone surface, for example to help steeror guide device 180. In some embodiments, all blades on a device may beconfigured for optimal soft tissue cutting, such as cutting ofligamentum flavum tissue in the spine, while in other embodiments allblades may be configured for optimal bone cutting, such as vertebralbone. Other alternative embodiments may include a combination of bladeshapes and configurations to provide multiple different types ofcutting. Further discussion of blades combinations and configurationsfollows below.

With reference now to FIG. 47, an alternative embodiment of a tissuemodification device 190 may include an elongate body having alongitudinal axis 191, a rigid shaft portion 193 and a flexible portion194. Flexible portion 194 may have a lateral axis 195 and may include aguidewire coupler 198 at or near it distal end. In some embodiments,multiple blades 196, 196′ may be disposed laterally across a first majorsurface 192 of flexible portion 194, with each set of two blades 196,196′ extending from a base 197 coupled with surface 192. The embodimentshown includes pointed-tip blades 196 and flat-top blades 196′. In theembodiment shown, and as described in further detail below in relationto an alternative embodiment, some or all blades 196′ may be angled,relative to elongate body longitudinal axis 191. Angling blades 196′ maycause or facilitate lateral movement of device 190 along a target tissueas device 190 is reciprocated back and forth to modify the tissue, thusproviding for wider or more complete tissue modification/removal.

Referring to FIG. 48, a flexible portion 204 of an alternativeembodiment of a tissue modification device 200 is shown in top view. Inthis embodiment, flexible portion 204 has a longitudinal axis 202, andmultiple sets of blades 206, each set of two blades extending from anassociated base 207, coupled with a first surface of flexible portion204. The sets of blades 206 may be distributed axially alonglongitudinal axis 202 and may also be distributed laterally across thefirst major surface. In the embodiment shown, three blades 206 a arealigned such that their sides are approximately in line withlongitudinal axis 202, while two blades 206 b are angled, such that eachside forms an angle 208 with longitudinal axis 202. Again, such angledblades 206 b may facilitate lateral movement or “steering” of device 200along a target tissue such as soft tissue and/or bone. In variousembodiments, all blades 206 may form an angle of about 0 degreesrelative to longitudinal axis 202 (as with blades 206 a), all blades maybe angled (as with blades 206 b), or device 200 may include acombination of angled and non-angled blades. In some embodiments, eachblade side may form an angle of between about 0 degrees and about 45degrees with longitudinal axis 202 of flexible portion 204. As mentionedpreviously, such blades 206 may be referred to as being “substantiallyin-line.” In a more preferred embodiment, each blade side may form anangle of between about 0 degrees and about 30 degrees relative tolongitudinal axis 202. In various alternative embodiments, any number orcombination of blades, having any combination of angles, positions onflexible portion 204 or the like may be used.

In various embodiments, blades may be distributed in any of a number ofsuitable distances and configurations along the first major surface offlexible portion 204. For example, any number of blades 206 may be usedin various embodiments, such as but not limited to between two and eightsets of two blades 206 each. In some embodiments, blades 206 aredistributed axially along flexible portion 204 at distances selected toconfer a desired amount of flexibility to flexible portion 204.Increased space between the sets of blades, for example, may increasethe flexibility of flexible portions 204, while placing the sets ofblades closer together along longitudinal axis 202 may decreaseflexibility of flexible portion 204.

Referring now to FIG. 49A, one embodiment of a tissue modificationdevice 210 is shown in end-on view at the location of a flexible portion214 with multiple blades 216 coupled with one side. Each set of twoblades 216, in this embodiment, extends from a base 215, and each base215 is coupled with flexible portion 214. As seen in this figure, insome embodiments some or all blades 216 may be laterally offset,relative to one another, along flexible portion 214. Blades 216 ofdevice 210 are substantially vertical, relative to the surface offlexible portion 214 to which they are attached, and they are alsoaligned at approximately a 0 degree angle relative to the longitudinalaxis of flexible body 214. In device 210, blades form approximately a 90degree angle with flexible body 214 and approximately a 0 degree anglewith the longitudinal axis of flexible body 214.

FIG. 49B shows an alternative embodiment of a tissue modification device220, again in end-on view, where rows of closely spaced blades 226 areattached together on flexible portion 224, analogous to the way sharks'teeth are aligned in rows in a shark's mouth. In this embodiment, setsof six blades 226 (three on each side) extend from one base 225, andeach base 225 is coupled with flexible portion 224.

FIG. 49C shows an alternative embodiment of a tissue modification device230 with four, flat-top blades 236 aligned at an angle relative to thelongitudinal axis of flexible portion 234. In this embodiment, each setof two blades 236 extends from an associated base 235.

FIG. 49D shows another alternative embodiment of a tissue modificationdevice 240, including two blades 246 that form an approximately 90degree angle 248 with a first major surface of a flexible portion 244and two blades 246′ that form a more acute angle 248′ with the firstmajor surface. In various embodiments, the sides of each blade may forman angle with the flexible portion of between about 90 degrees and about45 degrees, or more preferably between about 90 degrees and about 60degrees. These angles 248, 248′ maybe referred to as “tilt,” and in anygiven embodiment, all blades may be tilted (i.e., all form an angle ofless than 90 degrees with the surface), no blades may be tilted (i.e.,all form an angle of about 90 degrees with the surface), or some bladesmay be tilted and others may not, as in FIG. 49D.

Referring now to FIG. 50, as mentioned previously, in some embodiments,a tissue modification device 250 may have a flexible portion 254including multiple blades 256, some of which may be laterally offsetrelative to one another and others of which may lie along the same linerelative to one another. For example, device 250 includes multipleblades 256, all aligned at approximately 0 degrees relative to alongitudinal axis 252 of flexible portion 254. Blades 256 a and 256 dlie along the same line, relative to each other, as do blades 256 b and256 c. Obviously, blades 256 a and 256 d are offset, relative to blades256 b and 256 c. Blades 256 e and 256 f lie along the same line relativeto one another and are placed close to opposite edges of flexibleportion 254. In various embodiments, any combination of lateralplacement of blades 256 along device 250 may be used. Offsetting blades256 relative to one another may facilitate cutting or shredding of softtissue, for example.

In some embodiments, blades 256 may be shaped and/or axially spaced tofacilitate or enhance the collection of cut tissue between blades 256.(By “axially spaced,” it is meant the longitudinal spacing alonglongitudinal axis 252.) In some embodiments, axial spacing of blades 256may also be optimized to provide a desired flexibility to flexibleportion 254.

With reference now to FIGS. 51A-51E, a method according to oneembodiment is demonstrated for removing tissue using a tissuemodification device 260. FIG. 51A is an end-on, diagrammaticrepresentation of an intervertebral foramen IF, showing vertebral bone,ligamentum flavum LF and nerve root N, with device 260 passing throughthe foramen IF between nerve root N and ligamentum flavum LF. Device 260may have some blades 262 vertically oriented and at approximately a 0degree angle relative to the longitudinal axis of device 260, whileother blades 262′ may be angled, relative to the longitudinal axis.

In FIG. 51B, device 260 has been pulled upward (hollow-tipped arrows) tourge blades 262, 262′ into ligamentum flavum LF so that at least one ofblades 262, 262′ contacts vertebral bone. In some embodiments, some orall of blades 262, 262′ may have a height approximately equal to orgreater than a thickness of an average ligamentum flavum LF.

Referring to FIG. 51C, when device 260 is reciprocated back and forthalong its longitudinal axis, ligamentum flavum LF tissue is removed inone area of the intervertebral foramen IF. As device 260 isreciprocated, angled blades 262′ may steer or guide device 260 laterallyin the intervertebral foramen IF (hollow-tipped arrow). In someembodiments, for example, device 260 may steer to one side when thedevice is pulled in one direction and steer to the other side when thedevice is pulled in the opposite direction.

In FIG. 51D, device 260 has moved toward the opposite lateral side ofthe intervertebral foramen IF (hollow-tipped arrow) to remove additionalligamentum flavum LF tissue. In some embodiments, any or all blades 262,262′ of device 260 may have flat tops, which may help blades 262, 262′to slide or “skate” across the surface of bone as device 260 isreciprocated to cut through soft tissue. This sliding or skating motionmay also help device 260 move from side to side within theintervertebral foramen IF.

In FIG. 51E, much of the ligamentum flavum LF has been removed, andblades 262, 262′ are in a position to treat bone. In some cases, aphysician may choose to continue using device 260 to remove bone, whilein other cases a physician may wish to remove mostly or exclusivelyligamentum flavum LF tissue. In various embodiments, the physician maydetermine when a desired amount of soft tissue and/or bone is removed byusing tactile feedback from device 260, by removing device 260 toexamine tissue trapped in device 260, by radiographic visualization suchas fluoroscopy, by use of one or more sizing probes or other instrumentsto gauge the size of the intervertebral foramen IF, or any combinationof such methods.

When a desired amount of tissue has been removed, device 260 may beremoved from the patient to complete the procedure. As mentioned, insome embodiments, device 260 may be used to remove only ligamentumflavum LF tissue and then removed from the patient to end the procedure.In alternative embodiments, device 260 (or a differently configureddevice) may be used to remove both soft tissue and bone. In yet anotheralternative embodiment, a first device (for example, device 260) may beused to remove ligamentum flavum LF tissue, the first device may beremoved from the patient, and a second device may be inserted and usedto remove bone. Thus, in some embodiments, two different devices may beused in one procedure, with one device optimized for soft tissue removaland another device optimized for bone removal.

With reference now to FIGS. 52-55, various embodiments of bladestructures are shown. For example, in an embodiment as in FIG. 52, ablade structure 270 may include two blades 272 extending substantiallyvertically from a base 274. In some embodiments, each set of two blades272 and their associated base 274 may be made from one piece ofmaterial, with each blade 272 bending upward from base 274. Base 274 mayprovide a surface for attaching blades 272 to one side of a tissuemodification device, such as my welding, attaching via adhesive and/orthe like. In one embodiment, blades 272 may have beveled cutting edgesand pointed tips, as shown, although any of a number of other bladeconfigurations may alternatively be used.

In an alternative embodiment, as in FIG. 53, a blade structure 280 mayagain include two blades 282 extending substantially vertically from abase 284. In this embodiment, blades 282 have beveled edges and a flat,beveled top.

In another alternative embodiment, as in FIG. 54, a blade structure 290may include any number of blades 292 coupled with a base 294. In thisembodiment, twelve blades 292 are coupled with base 294, and base 294has a back-and-forth (or “zig-zag”) configuration.

In another alternative embodiment, as in FIG. 55, a blade structure 300may include eight, flat-top blades 302 (or any other suitable number)coupled with a base 304 having a diagonal configuration. When base 304is attached to a surface of a tissue modification device, blades 302 maybe angled and/or laterally offset due to the diagonal configuration ofbase 304.

Referring now to FIG. 56, one embodiment of a tissue modification device310 may include an elongate body flexible portion 312 and multipleblades 314 attached to one side of flexible portion 312 such that eachblade 314 has a height 316 and a length 319, and such that a distancebetween two blades 314 defines a pitch 318. As mentioned previously, invarious embodiments, blades 314 may have any of a number of shapes, suchas pointed-tip 314 a, 314 b and flat-top 314 c, 314 d. Each blade 314may also have a height 316, which may be defined as a distance betweenof first end of the blade 314, which is coupled with a first surface offlexible portion 312, and a second, cantilevered end of the blade 314.In some embodiments, for example, blades 314 have each have a heightranging from about 0.5 mm to about 2.0 mm. In some embodiments, two ormore blades may have different heights relative to one another. In oneembodiment, for example, one or more sets of blades 314 may have aheight optimized for addressing bone and one or more other sets ofblades 314 may have a height optimized for addressing soft tissue. Inone embodiment, shorter blades 314 may be positioned more distally onflexible portion 312, relative to higher blades 314 positioned moreproximally. This placement of blades 314 may facilitate entry of device310 into a tight anatomical location on a patient or around a tightcorner.

Length 319 of each blade 314 may be defined as a distance between twoblade edges. In various embodiments, blades 314 may have any suitablelengths, and a variety of blade lengths may be used in the sameembodiment. Blades 314 may also have a pitch 318, defined as a distancefrom the beginning of an edge of one blade 314 a to the beginning of anedge of a next adjacent blade 314 b along device 310. In someembodiments, for example, pitch 318 may range from about 0.5 mm to about4.0 mm. In various embodiments, any suitable combination of bladeshapes, heights 316, lengths 319 and pitches 318 may be used.

With reference now to FIG. 57, in another embodiment, a tissuemodification device 320 may include multiple blades 324 formed directlyout of a flexible portion 322, thus creating an opening 326 in flexibleportion 322. For example, blades 324 may be cut and bent out of flexibleportion 322. Flexible portion 322 may also include a guidewire coupler323. In this embodiment, flexible portion 322, blades 324 and guidewirecoupler 232 are formed from one piece of material.

Referring to FIG. 58, in another alternative embodiment, multiplesubstantially vertical, substantially in-line blades 334 may be formedin a flexible portion 332 of a tissue modification device by cuttingmultiple flaps in flexible portion 332 and pulling them up to formblades 334 (curved, hollow-tipped arrows). In some embodiments, flexibleportion 332 may be curved.

Referring now to FIGS. 59-76, a number of different embodiments ofblades, which may be included in various embodiments of tissuemodification devices, are shown. This is not meant to be anall-inclusive list, but instead is provided for exemplary purposes.Thus, other blades shapes and configurations not shown in FIGS. 59-76may also be used in various embodiments of tissue modification devices.

The blade embodiments shown and described below generally have more thanone cutting edge, and generally each edge of each blade is a cuttingedge. In various alternative embodiments, however, a blade may havemultiple edges, but not all the edges need be cutting edges. Forexample, in some embodiments a blade may have a cutting edge on one sideand a dull edge on an opposite side, thus acting as a one-directioncutting blade. In another embodiment, a blade may have a front edge, aback edge and a top edge, and only the front and back edges might becutting edges, with the top edge being dull, for example to facilitatethe blade's riding along a bone surface. Generally, any edge of a bladedescribed below may be, in alternative embodiments, a cutting edge or anon-cutting edge. Cutting edges, generally, may have any of a number ofdifferent configurations, such as beveled, pointed, serrated,saw-toothed and the like. Non-cutting edges may also have any of anumber of different configurations, such as squared, rounded, notched orthe like.

The blades of FIGS. 59-62 are all generally triangle-shaped. FIG. 59shows a triangle-shaped, pointed-tip blade 340 with tapered cuttingedges. FIG. 60 shows a triangle-shaped, pointed-tip blade 346 withstraight cutting edges. FIG. 61 shows a triangle-shaped, pointed-tipblade 352 with downward-facing barbs on two cutting edges. FIG. 62 showsa triangle-shaped, pointed-tip blade 358 with saw-tooth cutting edges.

FIGS. 63 and 64 show square-shaped blades. FIG. 63 shows a square-shapedblade 364 with a flat-top cutting edge and straight vertical cuttingedges. FIG. 64 shows a square-shaped blade 370 with straight verticalcutting edges and a crown-shaped (or serrated or saw-tooth) upperhorizontal cutting edge.

The blades in FIGS. 65-67 all have convex-shaped upper cutting edges. InFIG. 65, blade 376 has a convex upper cutting edge and concave lateralcutting edges. In FIG. 66, blade 382 has a convex upper cutting edge andstraight lateral (or vertical) cutting edges. In FIG. 67, blade 388 hasa convex, crown-shaped (or serrated or saw-tooth) upper cutting edge andstraight lateral cutting edges.

The blades in FIGS. 68-70 are all wave-shaped. The blade 394 of FIG. 68has a wave shape and two smooth cutting edges. The blade 400 of FIG. 69has a wave shape, one smooth cutting edge and one saw-tooth (orserrated) cutting edge. The blade 406 of FIG. 70 has a wave shape andtwo saw-tooth cutting edges.

FIGS. 71-73 all show rounded blades. In FIG. 71, blade 412 is roundedwith a smooth cutting edge. In FIG. 72, blade 418 is rounded withdownward facing barbs along a portion of its cutting edges. In FIG. 73,blade 424 is rounded with a saw-tooth (or serrated) cutting edge.

The blades of FIGS. 74-76 are all trapezoidal in shape. In FIG. 74,blade 430 has a trapezoidal shape and straight/smooth cutting edges. InFIG. 75, blade 436 has a trapezoidal shape and saw-tooth (or serrated)cutting edges. In FIG. 76, blade 442 has a trapezoidal shape andstraight lateral cutting edges with a saw-tooth (or serrated) uppercutting edge. Again, the foregoing examples are provided for exemplarypurposes, and in various embodiments, tissue modification devices mayinclude any alternative blade shapes and configurations.

FIGS. 77-82 are cross-sectional views of a number of different bladeembodiments, looking from an end-on perspective. According to variousembodiments, blades may have any of a number of different upper cuttingsurfaces, and FIGS. 77-82 illustrate several examples of such surfaces.In FIG. 77, for example, blade 450 includes an upper cutting edge havinga double-bevel configuration. The blade 454 in FIG. 78 has asingle-bevel upper cutting edge 456. In FIG. 79, blade 458 has a taperedshape that ends in upper cutting edge 460.

In some embodiments, a blade may have an upper surface that is not sharpor pointed. Such an upper surface may help such a blade to slide orskate off of a bony surface, thus facilitating steering of a tissuemodification device. For example, in FIG. 80, blade 462 has a flat uppersurface 464. In FIG. 81, blade 466 has a rounded (or convex) uppersurface 468. In FIG. 82, blade 470 has a concave upper surface 472.Again, any other suitable blade shape may be used in various alternativeembodiments.

Referring now to FIGS. 83A and 83B, a tissue modification device 402 hasa rigid proximal shaft portion 404 from which a flexible portion 406extends axially. A plurality of tissue modification elements in the formof blades 408 extend from a first surface 410 of flexible portion 406,as described above. Flexible portion 406 is advanced into a patient bodyso that first surface 410 is bent over a target tissue, with the targettissue here comprising both ligament 412 and bone 414. First surface 410of flexible portion 406 is wrapped over an at least partially convexsurface 416, with the convexity of the surface defining an inwardorientation 418 and an outward orientation 420. Hence, axial tension 422on the flexible portion 406 causes the first surface 410 to moveinwardly toward the target tissue 412, 414.

Referring still to FIGS. 83A and 83B, the surface 416 of the targettissue need not, and often will not, be substantially cylindrical, butwill often instead have portions that are more inward 418, and otherportions that are more outward 420. For example, a first portion orregion of the surface 416 adjacent a first edge 424 of flexible portion406 may be significantly more outward 420 than a region of the surfacethat is adjacent an opposed edge 426 and engagement between the flexibleportion and tissue surface. As a result of the axial tension 422 in theflexible portion 406, this difference can cause the flexible portion torotate about its central axis. Continued reciprocation of the flexibleportion when its rotational orientation is not adequately controlledcould cause an edge 426 of the flexible portion to cut laterally intotarget tissues as illustrated in FIG. 83B, or even inadvertent flippingof the flexible portion which might expose non-target tissue 430 todamage from the cutting blades along first surface 410, rather thaneffecting controlled volumetric removal of the target tissue.

To inhibit uncontrolled rotation of the flexible portion 406, the rigidshaft of proximal portion 404 significantly improves the control overboth the orientation and position of the flexible portion, in part bytransmitting torque 432 from the proximal handle to the treatment sitewithin the patient. By rotating (or restraining) the proximal handleabout the axis of the shaft, torque is transmitted down the shaft and tothe flexible portion adjacent the target tissue. The torque can betransmitted so as to inhibit rolling or flipping of the flexibleportion, and can also be used to intentionally alter an orientation ofthe flexible portion and tissue modifying members. The proximal handleand/or proximal portion may have an asymmetric shape or some asymmetricindicia that identifies the orientation of the tissue modifying membersto enhance the physician's control over the orientation of tissue beingmodified and/or removed.

Referring now to FIGS. 84A and 84B, additional aspects of the structureand use of rigid shaft proximal portion 404 to control the location andorientation of distal flexible portion 406 can be understood. Asgenerally described above, tissue modification tool 402 is generallypositioned for use with rigid portion 404 extending a proximal handle440 through an open or minimally invasive surgical axis site to flexibleportion 406, with the flexible portion often extending distally from anaxis 442 of the proximal portion. The distal flexible portion 406 alsohas a central axis which extends around a target tissue to a distal endthat is coupled to a guidewire 444 extending out of the patient, with adistal handle 446 being axially affixable to the guidewire so thattension can be applied to the flexible portion 406 by pulling upward onthe proximal and distal handles 440, 446.

As described above, torqueing the shaft of rigid portion 404 about itsaxis using handle 440 (as schematically illustrated by arrows 448) canhelp to orient the tissue treatment member(s) along the first surface410 of flexible portion 406 toward a target region of the target tissue.Additionally, it will often be desirable to shift flexible portion 406laterally relative to its central axis, that is, into and/or out of theillustration of FIG. 84B. Handle 440 can be used to help move flexibleportion 406 using one or both of two techniques. First, handle 440 canbe pushed laterally relative to the axis 450 of the rigid proximal shaftportion 404 as illustrated by arrows 452. Where handle 440 laterallytranslates the shaft without rotating of the shaft, end 454 of rigidportion 404 may also translate laterally, thereby laterally shifting theflexible portion 406. Alternatively, handle 440 may be used to pivot therigid portion 404 about an effective pivot point 456 (as schematicallyillustrated by curving arrows 458), similarly effecting lateral movementof the end 454 of the rigid portion within the patient. Some combinationof lateral movement of the overall rigid portion 404 will often becombined with some pivoting of the rigid portion. The pivot point 456 isnot necessarily at a fixed location in space, and may move somewhat asthe tissues adjacent the tissue modification tool 402 are displacedand/or compressed.

As described above, guidewire 444 advantageously allows tension to beapplied to a distal end 460 of flexible portion 406, optionally allowingthe flexible portion to be shifted and/or positioned along its curvingaccess for treatment of a target tissue, as well as allowing distractionof target tissues, reciprocation of the tissue modification elements andflexible portion against a target tissue, and the like. To enhancelateral and rotational control over the flexible portion 406, andparticularly the length of the flexible portion close to its distal end460, a second rigid shaft 462 may be affixed to distal handle 446. Thesecond shaft 462 may have a central lumen that receives guidewire 444therethrough. Second shaft 462 may then be manipulated as describedabove regarding the rigid portion 404, allowing the distal end 460 ofthe flexible portion to be shifted in coordination with the shiftingeffected by the rigid portion 404. This may enhance overall control overthe lateral movement of flexible portion, optionally using the pivotingand/or lateral movement techniques described above. The second rigidshaft 462 will often have a distal end with a profile suitable foradvancing distally over guidewire 44 toward the target tissue, and mayalso torquably engage the distal end of flexible portion 406 so as toallow the distal end to be torqued about the longitudinal axis of theflexible portion and guidewire (such as by providing a slot in theinserted end of second shaft 462 to torquably receive the distal end ofthe flexible portion).

Referring again to FIGS. 51A-51E, it will often be desirable to removetarget tissue from a tissue region 259 which is wider than an adjacenttissue modification device 260. Additionally, it may be desirable toreorient the tissue modification members carried by a flexible portionof a tissue modification device 260 so as to treat portions of thetarget tissue that are at different angles. As described above,tensioning of tissue modification device 260 using the proximal anddistal handles can urge the tissue modifying members toward a firstregion of the target tissue, such as the region being engaged by blades262, 262′ in FIG. 51B. As this tissue is removed, the tension will tendto keep the tissue modification device 260 at the removed tissuelocation. Optionally, the orientation of the tissue modification device260 may be rotated about a central axis of the flexible portion of thetissue modification device by rotation of rigid portion 404 (see FIGS.83A, 84A), resulting in lateral rotation of the flexible portion andtissue modification elements carried thereby in a counter-clockwisedirection (see FIG. 51C) wherein a clockwise direction (see FIG. 51D).Additionally, lateral translation and/or pivoting of the rigid portion404 about pivot point 456 may be used to laterally shift or translatethe tissue treatment device 260.

Lateral shifting of the flexible portion may be facilitated (forexample) by including tissue modification devices or blades havingsufficient length to extend through ligament target tissue such as theligamentum flavum, and by including tips on at least some of the tissuemodification devices or blades that are large enough to avoidpenetrating into underlying bone. This may allow the flexible substrateto ride over the tough ligament, facilitating lateral movement of theoutermost blades into target ligament tissues. Lateral shifting of theflexible portion may also be facilitated by a flexible substratestructure which is relatively stiff in one lateral orientation(specifically, along the major surfaces) and more flexible in anotherlateral orientation (transverse to the major surfaces, so as to allowthe flexible member to bend over the target tissue with a major surfaceoriented toward the target tissue). Advantageously, such selectivelateral flexibility and lateral stiffness can be readily provided by athin, flat substrate having a cross-section that includes a much largermoment in one orientation (for example, bending in the plane of themajor surfaces) than another (for example, bending in the plane of thesmaller edges).

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

Devices and Methods for Tissue Modification

The present invention relates to methods and apparatus for selectivesurgical removal of tissue, such as for the treatment of spinal neuraland neurovascular impingement, through selective resection, ablation,and remodeling of tissue in the lateral recess, neural foramina andcentral spinal canal, more particularly, for safely performing lateralrecess and neuroforaminal enlargement of the spine.

Pathological compression of spinal neural and neurovascular structuresis an age-related process, increased in prevalence and severity inelderly populations, with potential congenital anatomic components, thatresult in back, radicular extremity pain and both neurological (e.g.,sensory) and mechanical (e.g., motor) dysfunction. Prevalence is alsoinfluenced by congenital spinal anatomy. Disease progression leads toincreased neural irritation, impingement, and ischemia, and isfrequently accompanied by progressively increased pain, often inconjunction with reflex, sensory and motor neurological deficits.

In the United States, Spinal Stenosis occurs with an incidence ofbetween 4 percent and 6 percent of adults 50 years of age or older, andis the most frequent reason cited for back surgery in patients 60 yearsof age and older.

Spinal Stenosis often includes neural or neurovascular impingement,which may occur in the central spinal canal, the lateral recesses of thespinal canal, or in the spinal neural foramina. The most common causesof neural compression within the spine are spinal disc disease(collapse, bulging, herniation); ligamentum flavum buckling, thickeningand/or hypertrophy; zygapophysial (facet) joint hypertrophy; osteophyteformation; and spondylolisthesis.

Disease progression increases neural irritation, impingement, andischemia, and is frequently accompanied by progressively increased pain,often in conjunction with reflex, sensory and motor neurologicaldeficits.

Current surgical treatments for Spinal Stenosis include laminectomy(usually partial, but sometimes complete) and/or facetectomy (usuallypartial, but sometimes complete), with or without fusion. While standardsurgical procedures lead to improvements in symptoms for 6 months ormore in approximately 60% of cases, there is an unacceptable incidenceof long-term complications and morbidity.

Several companies offer tools that facilitate surgical access to theareas of the spine where neural impingement is likely to occur, in orderto allow the surgeon to decompress the impinged neural structuresthrough the removal of vertebral lamina, ligamentum flavum, facetcomplex, bone spurs, and/or intervertebral disc material. These surgicalresections are frequently (i.e., occurs in 15% to 20% of cases)accompanied by fusion (arthrodesis). Spinal arthrodesis is performed tofuse adjacent vertebrae and prevent movement of these structures inrelation to each other. The fusion is commonly a treatment for pain ofpresumed disc or facet joint origin, for “unstable spines”, and forspines that have been rendered “unstable” by the surgical decompressionprocedures, as described above. The definition of “spinal instability”remains controversial in current literature.

Spinal arthrodesis may be achieved through various surgical techniques.Biocompatible metallic hardware and/or autograft or allograft bone iscommonly secured anteriorly and/or posteriorly in the vertebral columnin order to achieve surgical fusion. These materials are secured alongand between the vertebral bodies (to restore vertebral height andreplace disk material) and/or within the posterior elements, typicallywith pedicle screw fixation. Autograft bone is often harvested from thepatient's iliac crest. Cadaveric allograft is frequently cut in discshaped sections of long bones for replacement of the intervertebraldiscs in the fusion procedure.

Critics have frequently stated that, while discectomy and fusionprocedures frequently improve symptoms of neural impingement in theshort term, both are highly destructive procedures that diminish spinalfunction, drastically disrupt normal anatomy, and increase long-termmorbidity above levels seen in untreated patients.

The high morbidity associated with discectomy may be due to severalfactors. First, discectomy reduces disc height, causing increasedpressure on facet joints. This stress leads to facet arthritis and facetjoint hypertrophy, which then causes further neural compression. Thesurgically-imposed reduction in disc height also may led toneuroforaminal stenosis, as the vertebral pedicles, which form thesuperior and inferior borders of the neural foramina, become closer toone another. The loss of disc height also creates ligament laxity, whichmay lead to spondylolisthesis, spinal instability or osteophyte or “bonespur” formation, as it has been hypothesized that ligaments may calcifyin their attempt to become more “bone-like”. In addition, discectomyfrequently leads to an incised and further compromised disc annulus.This frequently leads to recurrent herniation of nuclear materialthrough the expanded annular opening. It may also cause further bucklingof the ligamentum flavum. The high morbidity associated with fusion isrelated to several factors. First, extensive hardware implantation maylead to complications due to breakage, loosening, nerve injury,infection, rejection, or scar tissue formation. In addition, autograftbone donor sites (typically the patient's iliac crest) are a frequentsource of complaints, such as infection, deformity, and protracted pain.Perhaps the most important reason for the long-term morbidity caused byspinal fusion is the loss of mobility in the fused segment of the spine.Not only do immobile vertebral segments lead to functional limitations,but they also cause increased stress on adjacent vertebral structures,thereby frequently accelerating the degeneration of other discs, joints,bone and other soft tissue structures within the spine.

Recently, less invasive, percutaneous approaches to spinal discectomyand fusion have been tried with some success. While these less invasivetechniques offer advantages, such as a quicker recovery and less tissuedestruction during the procedure, the new procedures do not diminish thefact that even less invasive spinal discectomy or fusion techniques areinherently destructive procedures that accelerate the onset of acquiredspinal stenosis and result in severe long-term consequences.

Additional less invasive treatments of neural impingement within thespine include percutaneous removal of nuclear disc material andprocedures that decrease the size and volume of the disc through thecreation of thermal disc injury. While these percutaneous procedures mayproduce less tissue injury, their efficacy remains unproven.

Even more recently, attempts have been made to replace pathologicaldiscs with prosthetic materials. While prosthetic disc replacement is arestorative procedure, it is a highly invasive and complex surgery. Anysynthetic lumbar disc will be required to withstand tremendousmechanical stresses and will require several years of development beforeit will achieve the longevity desired. Further, synthetic discs may notbe an appropriate therapeutic approach to a severely degenerative spine,where profound facet arthropathy and other changes are likely toincrease the complexity of disc replacement. Like most prostheticjoints, it is likely that synthetic discs will have a limited lifespanand that there will be continued need for minimally invasive techniquesthat delay the need for disc replacement. Even if prosthetic discsbecome a viable solution, a simpler, less invasive approach torestoration of functional spinal anatomy would play an important role inthe treatment of neural impingent in the spine. The artificial discs inU.S. clinical trials, as with any first generation prosthesis, are boundto fail in many cases, and will be very difficult to revise forpatients. The prostheses will, therefore, be best avoided, in manycases. Lumbar prosthetic discs are available in several countriesworldwide.

In view of the aforementioned limitations of prior art techniques fortreating neural and neurovascular impingement in the spine, it would bedesirable to provide methods and apparatus for selective surgicalremoval of tissue that reduce or overcome these limitations.

The present invention relates to methods and apparatus for the selectivesurgical removal or alteration of tissue that impinges upon spinalneural or vascular structures, with particular attention towardsavoiding injury to the affected or adjacent neural and neurovascularstructures. More particularly, a preferred embodiment of the presentinvention relates to methods and apparatus for lateral recess 60108 andneural foraminal enlargement of the spine, in cases of neurovascularimpingement, through a novel approach to selective and safe enlargementof the pathologically narrow spinal neural foramen 60110, impingedlateral recess 60108 and/or compromised central spinal canal. Tissuesthat impinge the spine's central canal, lateral recess 60108, and neuralforamen 60110 may include, but are not limited to, ligamentum flavum6010; bone spurs or ligamentous calcifications; localized discextrusions; enlarged facet joint complex 6012, facet capsule, andsuperior articular processes; and scar tissue or adhesions.

The variations of the invention designed to treat spinal stenosis aresummarized in this paragraph, and described in greater detail in theparagraphs that follow. The methods begin with insertion of an epiduralneedle 602 apparatus, which is converted, after placement in theepidural space, from a sharp tipped instrument, into a blunt tippedtool. The blunt tool is manipulated within the epidural space. Accuratetool manipulation may be facilitated with the use of image guidance;direct vision via an accompanying epidural endoscope; or direct visionwhen the instrument itself is given endoscopic function. The same blunttipped epidural instrument may have an attached fixed or removableworking channel. An additional apparatus of the current invention, aworking backstop or barrier 6096 that serves to protect adjacentvulnerable structures during the procedure, may subsequently be insertedinto the epidural space, as well as through the neural foramina, throughthe needle or endoscope or an adjacent working channel. Safe resection,ablation, and remodeling may be further ensured through integration intothe invention of electrical neural stimulation and monitoring forlocalization, optionally available through nerve stimulationfunctionality in the epidural instrument; in the working tools usedthrough the needle or working channel; and/or in either or both sides ofthe working backstop 6096. Finally, further variations of the device andmethod enable the surgeon to remodel stenotic spinal anatomy, eitherafter tissue resection, cutting, or abrasion or as stand-aloneprocedures, through the placement of devices for holding, retracting orretaining anatomic structures away from vulnerable neural andneurovascular structures within the posterior elements of the spine.

FIG. 85 shows the posterior elements of the spine in axial crosssection. The epidural space 6042 in the spine is consistently moreaccessible in its posterior most aspect, a fat filled zone most popularfor safe epidural needle 602 placement, posterior to the dura mater6046. The dura 6046 covers and contains the central neural elements ofthe spine, including the spinal cord, cauda equina 60140, nerve roots6062, and spinal fluid. FIG. 86 illustrates the spine in sagittalsection. FIGS. 85 and 86 show two of the most important anatomicstructures involved in the impingement of neural and neurovasculartissue in spinal stenosis—the ligamentum flavum 6010 and the facet jointcomplex 6012. FIG. 86 illustrates spinous processes 6080.

For posterior approaches to the lateral recess 60108 and neural foramen60110, the needle 602 is inserted at or one level below the spinalinterspace where tissue abrasion and removal is desired. The epiduralneedle 602 may be inserted into the epidural space 6042, midline,ipsilateral, or contralateral to the area where the spinal canal,lateral recess 60108 and/or neuroforaminal stenosis or impingement is tobe treated. Referring now to FIG. 87, a prior art method for epiduralneedle 602 insertion is shown, comprising a standard loss-of-resistancetechnique. Needle based device placement may be approached from eitherthe medial or the lateral side of the neural foramen 60110. FIG. 87illustrate a midline interspinous approach to the posterior epiduralspace 6042. Using this technique, a large bore (e.g. 6012 to 6018 gauge)epidural needle 602 is inserted into interspinal ligaments, and isdirected towards the posterior epidural space 6042, while fluid (e.g.sterile saline) or air is compressed within the syringe 6060, meetingresistance to injection. Upon entry of the needle tip into the epiduralspace 6042, perhaps through the ligamentum flavum 6010, there is amanually perceptible “loss of resistance” to the continued pressure onthe plunger of the syringe 6060, as the compressed fluid or air easilyenters the epidural space 6042, without resistance, signifying correctneedle tip position (i.e., placement). The epidural space has a slightnegative pressure.

Alternative posterior epidural needle 602 entry approaches into theepidural space are illustrated in FIG. 88, including interlaminarparamedian and midline interspinous techniques, a preferred approach tothe medial side of the neural foramen 60110. An alternative posteriortranslaminar approach, where the needle is placed through a hole in thelamina 60122 [LA], is not shown. The epidural space may also be enteredvia a more lateral, neuroforaminal approach to needle placement, asshown in FIG. 155. With any percutaneous epidural approach, after asterile prep and drape, the epidural needle's 602 sharp tip is insertedthrough the skin to perform a loss-of-resistance technique.

When a midline approach is used, the epidural needle's 602 sharp tip isinserted through the skin until it begins to engage the interspinousligaments 6078. Subsequently, a fluid or air filled (loss of resistance)syringe 6060 is depressed and will meet resistance to injection, untilthe needle tip is advanced, through the ligamentum flavum 6010, enteringthe epidural space 6042, which actually has a slight negative pressure.There is a clear “loss of resistance” to the pressurized contents of thesyringe 6060, which occurs upon entering the epidural space 6042,signifying correct needle tip placement.

When interlaminar access is not possible (e.g. unusual cases whenlaminae 60122 are too tightly approximated, even with flexion of theback), the epidural space may be entered via a translaminar burr hole,using a drill 60176 (e.g., an image guided drill) designed for safeepidural entry. Each of these approaches allows placement of theepidural needle 602 tip in the posterior epidural space 6042, poised foraccess to the lateral recess 60108 and neural foramen 60110.

After the epidural needle's distal tip has been placed in the posteriorepidural space 6042, a specially designed epidural catheter 6024 isthreaded through the needle 602. Once threaded into the epidural space6042, the epidural catheter's unique epidural needle tip cap or cover6036, located in the distal end of the epidural catheter 6024 (withneedle tip covering capabilities) is opened and pulled back to cover thesharp epidural needle 602 tip, locked in place, and thereby converts theneedle to a non-sharp (e.g., blunt) instrument. The needle, thusconverted, may be manipulated and more safely advanced in the epiduralspace. The blunted needle is subsequently advanced in a directionparallel to the dura 6046, in a gentle manner, taking care to avoidinadvertent dural, neural or vascular trauma. With reference to FIGS.90, 92, 93, 94, 95, 96, and 97, methods and apparatus for protecting,covering and blunting the sharp tip of the epidural needle 602post-insertion, and optionally converting the epidural needle 602 to anepidural endoscope 60132, are described. The catheter apparatus 6024 isinserted through the needle, and into the epidural space 6042, as inFIGS. 6 b, 8 b, 9 a, 10 b, 85 b, 12 a, and 13 c. The catheter tip may beconverted to the open position by one of several mechanisms, forexample, the catheter illustrated in FIG. 609 has a port 6034 forinjection of air or liquid to the open the epidural needle tip cover.The injected air or liquid drives (e.g., opens) the actuator for thecatheter's tip (needle cover). By forcing air or fluid into port 6034 inthe epidural catheter 6024, a portion of the catheter's tip 6036 may beexpanded, as in FIG. 6 b, 8 c, 9 b, 11 c, 12 b, or 13 e, to inflate orotherwise open the needle's protective cover or cap 6036. In anothervariation, an alternative means of actuation of the cap system on theepidural catheter 6024 may be a wire or string that pulls the cap into anew shape. For example, FIG. 96 demonstrate a sliding umbrella-likemechanism for actuation of the distal epidural catheter 6024 basedneedle tip cover 6036. FIG. 9B shows the epidural “needle cap” or “fibercap” 6036 in the opened position. In certain embodiments, the cathetermay next need to be pulled back proximally through the needle 602 until,as in FIG. 9C, until the epidural needle cover 6036 is engaged over thedistal needle tip, protecting the dura 6046, neural and vascularstructures from the sharp point of the needle 602, which is no longerexposed. Markings on the catheter may be used to demonstrate to thesurgeon that the catheter is in the correct position, allowing theblunted epidural instrument to be safely advanced.

Once the tip of the epidural needle 602 has been blunted or capped, andno longer has a sharp exposed portion, the needle may be safely advancedwithin the epidural space, preferably in a direction parallel to thedura 6046 (FIG. 97). In one variation, the epidural needle 602 tip iscovered by the catheter based device, then is advanced through theepidural space under image guidance (e.g. fluoroscopy, CT, x-ray, MRI,Ultrasound, etc.), towards the area where tissue resection, ablation orremodeling is to be performed.

In an alternative variation of the method and device, as in FIGS. 92,93, 95, and 97, the epidural catheter 6024, in addition to a needle tipcover, also contains a fiberoptic cable 6038 (or clear cover over thedistal end of the fiberoptic cable within the epidural catheter), whichenables conversion of the epidural needle 602 into an epidural endoscope60132. The fiberoptic component 6038 of the catheter provides thesurgeon with an ability to directly visualize the epidural space 6042.In a further variation of the method, both fiberoptic visualization andimage guidance may be used concurrently.

In this apparatus and method for enabling safe manipulation of theapparatus in the epidural space, an epidural needle 602 is first placedin the posterior epidural space 6042 in a similar manner to what wasdescribed above. With the needle tip in the epidural space 6042, anepidural catheter 6024 apparatus is used to deliver a cover to the sharpepidural needle 602 tip, converting the needle to a blunt instrument forfurther atraumatic advancement of the apparatus into the epidural space,as shown in FIGS. 90, 93, 95, and 96. After the catheter 6024 isadvanced through the epidural needle 602 into the epidural space 6042,as in FIGS. 6 a and 9 a, a distal portion of the catheter is convertedto a shape that will be used to cover the sharp epidural needle 602 tip,as illustrated in FIG. 6 b.

Once the cover 6036 in the distal catheter 6024 is opened, the catheter6024 is gently pulled back until the needle tip is covered and therebyblunted. The capped needle is next carefully advanced within theepidural space 6042, between the ligamentum flavum 6010 and the dura6046, somewhat parallel to both, towards one of the neural foramen60110, with much less risk of inadvertent dural puncture. In order tofurther facilitate safe advancement of the capped needle in the epiduralspace, image guidance may be used. Additionally or alternatively, theepidural needle 602 may be converted to an epidural endoscope.Conversion to an endoscope may be performed by either converting theepidural needle 602 to an endoscope directly (“needlescope”), or byutilizing the epidural needle 602 to enable placement of an endoscopecannula or portal 6056, which will replace the needle 602. The needle602 may be converted to an endoscope directly through use of thecatheter 6024 that is used to cover, blunt, or “safe” the epiduralneedle 602 tip. The epidural catheter 6024 optionally may contain arigid or flexible fiberoptic element 6038, through which the surgeon mayview the epidural space 6042, thereby converting the epidural needle 602into an epidural endoscope. The tip of the fiberoptic catheter would, insuch a case, be clear 6038.

FIG. 91 illustrates a distal epidural anchor 6040. The distal epiduralportal anchor 6040 can, in its engaged position, hold the distal portionof the epidural apparatus in the epidural space, anterior to theligamentum flavum. FIG. 91 also illustrates that the portal, needle, orendoscope may include a proximal epidural anchor, stopper or lock 6028(e.g., to anchor on the skin) that may be advanced from the proximal endof the device (skin side), in order to help to prevent the percutaneousdevice from advancing further into the epidural space than is desired(as in FIG. 7 b). The lock 6028 can be inserted over the portal andagainst the skin when the portal is at a desired depth.

In a further variation of the apparatus and method, an epidural portal6056 would allow interchangeable epidural endoscopes to be used to viewor work within the epidural space. An epidural needle 602 may be used toplace an endoscope portal 6056, using one of the three following generalapproaches: (a) In one variation, a portal is an expandable catheter(e.g. FIG. 166) that is delivered as a catheter through the epiduralneedle 602; (b) In another preferred embodiment, an epidural needle 602may be inserted into the epidural space, with a thin walled epiduralcannula or portal 6056 already in place over it, similar to the methodand apparatus of standard intravenous cannulation with IV catheters usedtoday. This technique would ideally be used in conjunction with theepidural needle 602 method and apparatus, so that the needle may beadvanced far enough to safely also place the neck of the cannula orportal 6056, which is a short distance proximal to the distal tip of theepidural needle 602, into the epidural space. In order be able to safelyadvance the portal 6056 into the epidural space, the needle may becovered or blunted, as described above, using a catheter that does notcontain a fiberoptic element, as in FIG. 90. With the sharp tip covered,the needle may be subsequently advanced a few millimeters, until thedistal tip of the portal has also been advanced into the epidural space6042; (c) In a third embodiment of the method and apparatus, the portal6056 may be inserted over a soft tipped flexible guidewire that has beenplaced through the epidural needle 602, analogous to the popular“Seldinger Technique” (a standard cannula over needle insertion approachto vascular access).

With reference to FIG. 98, additional variations of the apparatus ofFIG. 93 are described, illustrating methods of safely utilizing theapparatus, in combination with additional surgical tools. Safe toolaccess, for example, may be facilitated by the inclusion of either aworking channel 6050 on an epidural endoscope, or by sliding the toolalong a rail 6052 and slot 6058 interface on the epidural cannula or“needlescope” 6056. FIG. 98A shows tool 6054 (illustratively a grasper)fitted with rail 6052 that mates with a slot 6058 of epidural endoscope,so that it may be inserted directly into the epidural space 6042 andplaced in the “safe zone”, without the need for a working channel alongendoscope/needle.

In FIG. 98B, working channel 6050 is disposed along epidural needle 602,“needlescope”, or endoscope, e.g., is integrally formed with theendoscope or is positioned via a rail and slot mating, or a similarremovable fastening mechanism, with the endoscope. FIG. 98B illustratesan epidural working channel 6050 in place, connected to the cannula,needle, or endoscope, with its tool-presenting end adjacent to the “safezone”.

In order to further facilitate working in the epidural space 6042, theepidural portal or cannula 6056 may have, preferably close to its distaltip, an anchor system 6040 to prevent said apparatus from inadvertentlyslipping out of the epidural space 6042, as illustrated in FIG. 91. Theanchor 6040 may be engaged towards the distal tip of the cannula orportal 6056, anterior to the ligamentum flavum 6010. The portal 6056 mayalso be anchored external to the epidural space 6042, e.g., to thepatient's skin 6070 (e.g., of the patient's back), or withininterspinous 6078 or supraspinous ligaments.

Referring now to FIG. 99, an additional method and apparatus forplacement of the tissue modification elements is illustrated. A twin(i.e., double) lumen epidural needle 6084 is illustrated, comprising aworking channel 6050 adjacent to the epidural needle 602. The secondlumen serves as a working channel 6050, or for the delivery of toolsinto or adjacent to the epidural space 6042. Note that the distalbeveled aperture of the working channel is proximal to the epiduralneedle 602 tip, and opens onto the side of the epidural needle 602 thatthe epidural bevel faces. The double lumen epidural needle 6084 can havea proximal bevel representing a working channel and a distal bevelrepresenting an epidural access needle and, potentially, an endoscopyport or an additional working channel.

Referring now to FIGS. 100-103 and 126-129, an additional method andapparatus for placement of a tissue abrasion apparatus for selectivesurgical removal or remodeling of tissue is described. In FIG. 100, thedouble lumen epidural needle apparatus is positioned for advancementinto the epidural space 6042. FIGS. 101 and 102 show how the covered andblunt tip of the epidural needle 602, double lumen epidural needle 6084,or the blunt end of the epidural endoscope, may be advanced into theipsilateral or contralateral lateral recess 60108, towards the neuralforamen 60110, in a direction parallel to both the adjacent ligamentumflavum 6010 and the dura 6046. In the illustrated example of theapparatus and method labeled FIG. 101, a fiberoptic element 6038 hasbeen placed within epidural needle 602, providing both a means forfiberoptic visualization of the epidural space 6042 and a means to bluntthe needle and thereby protect the tip of the needle from damaging thedura 6046 or neural or vascular structures. In FIG. 102, the endoscopehas been advanced along ligamentum flavum 6010 (visually yellow,otherwise known as “the yellow ligament”) to the lateral recess 60108.“Safe zone” 6044 designates the area in which a medical practitioner mayresect, ablate, or otherwise modify tissue safely, directly visualizingthe are of tissue modification through the fiberoptic element. The safezone 6044 is the area posterior to the apparatus in the epidural space,where dura is known to be on the other side of the apparatus, and istherefore a safe zone for tissue alteration without damaging dura orcentral nervous system structures, particularly when using fiberopticvisualization through the distal lumen. The second lumen of the twolumened needle 6084 or endoscope may be used as a working channel 6050,or to dispense the abrasive element 6014 and/or its protective sleeve606, or the working barrier described in the primary patent referencedherein. After the neural foramen 60110 has been cannulated with anon-sharp curved needle 6016 or catheter, and after the flexible, sharp,straight needle or wire 604 (e.g., a guidewire) has been passed throughthe curved needle 6016 until its tip is advanced through the skin in thepatient's back 6070, the abrasion apparatus 6014 and/or its sleeve orcover 606 are pulled through the neural foramen 60110, as illustrated inFIGS. 127-129. The curved needle 6016 or tube may, for example, befabricated from a spring steel, Nitinol, or other memory material thatwill allow it to be inserted through a straight needle, but to return toa fixed curve upon exiting the straight epidural needle 602 or workingchannel 6050. The curved needle 6016 optionally may be steerable.Preferably, the curved needle tip is not sharp, but is rounded ordesigned in other fashions less likely to cut tissue, in order to reducea risk of neural or vascular damage.

In yet an additional embodiment of the invention (“portal over epiduralneedle” variation), an epidural portal 6056 may be inserted into theepidural space 6042 as a catheter over the epidural needle 602 (as inFIG. 96), similar to the design for placement of standard intravenouscatheters used today. With such an approach, advancing the bluntedneedle (sharp tip covered) by several millimeters will also bring thedistal tip of the portal into the epidural space 6042. Subsequently, theneedle may be withdrawn from the portal, which is held in place by thesurgeons other hand, leaving the epidural portal in the epidural space6042 as a working channel or endoscope guide.

In one variation, the epidural needle 602, needle based endoscope,flexible or rigid endoscope, or portal 6056 (for placement over anepidural needle 602) may have, preferably close to its distal tip, an(e.g., distal) anchor mechanism 6040 and 6048 (in its un-engagedposition) that may be inflated or otherwise opened (e.g., in theepidural space 6042), to help prevent inadvertent removal of the devicefrom the epidural space 6042. It is expected that utilization of ananchor to, or within, the ligamentum flavum 6010, will prevent theportal from being pulled inadvertently through the ligamentum flavum,and will enhance the reliability and safety of epidural access forminimally invasive endoscopic surgery.

FIG. 98 illustrates additional methods of safely utilizing a bluntedepidural apparatus in conjunction with additional surgical tools. Safetool access may, for example, be facilitated with either a fixed workingchannel 6050, as shown in FIG. 99, or by the creation of a rail 6052 andslot 6058 interface on the tool or epidural endoscope, cannula or“needlescope” 60132, as shown in FIG. 6014 b. The working channel 6050can be insertable and removable and can be for attachment to theepidural apparatus. The rail portion 6052 of the epidural instrument canbe for guiding the epidural tools along the blunted epidural apparatusinto the epidural space. The slot portion 6058 of the epiduralinstrument or portal can be for guiding the epidural tool or workingchannel into the epidural space. Note the rail 6052 and slot 6058 may bereversed, with the rail 6052 on the sleeve or scope and the slot 6058 onthe tool or working channel.

FIG. 98 a shows a tool 6054 (illustratively a grasper) fitted with arail 6052 that mates with a slot 6058 of epidural endoscope 60132, sothat it may be inserted directly into the epidural space 6042 and thenadvanced until it is placed in the “safe zone” 6044 (e.g., for tissueresection or modification, on an opposite side of the epidural tissue),without the need for a working channel along endoscope/needle 60132. Thepart of the epidural tool that is expected to be in direct contact withthe impinging spinal tissues 60124 that the surgeon intends to modifyprovides an ideal location for neural stimulator lead placement 60130.In the example illustrated in FIG. 98 a, an insulated tool shaft iscombined with a conductive surface 60130 on the tip of the grasping tool6054, to be used for neural stimulation. (note: the use of neuralstimulation with sensorimotor monitoring, for neural localization, inconjunction with the current invention, will be discussed later in thisdocument)

In one variation, the epidural needle 602 is curved towards its distalend, e.g into a hockey stick shape. In a curved configuration, the lumenexits the bevel, distal to, and on the concave side of the bend in theneedle's distal shaft. With such a configuration, a “safe zone” 6044 iscreated by inserting the needle so that the side opposite the bevel(convex side of the bend) is in direct contact with the dura, and thelumen, on the concave side of the bend, faces the ligamentum flavum.This configuration provides a “safe zone” 6044, where tools, or aworking channel 6050, may be reliably placed on the needle side oppositethe dura 6046.

In FIG. 98 b, a removable working channel 6050 is disposed alongepidural needle/endoscope 60132, e.g., is integrally formed with theendoscope or is positioned via a rail 6052 and slot 6058 mating with theendoscope 60132. FIG. 98 b illustrates an epidural “needlescope” 60132or endoscope cannula with the working channel 6050 in place, with itstool-presenting end adjacent to the “safe zone”.

Referring now to FIGS. 100-103, an additional method and apparatus forselective surgical removal of tissue is described. In FIG. 99, a doublebarrel epidural needle 60164 is illustrated, comprising a workingchannel 6050 adjacent to the epidural needle 602. In FIG. 100, thedouble lumen epidural needle apparatus is positioned for advancementinto the epidural space 6042 (e.g., a safe triangle, an area at the mostposterior aspect of the epidural space 6042, where epidural needle 602tip insertion is most consistently safely performed). In FIG. 101, acatheter based fiberoptic element 6038 has been placed within epiduralneedle 602, providing both a means for fiberoptic visualization of theepidural space 6042 and a means to blunt the needle and thereby protectthe tip of the needle from damaging the dura 6046 or neural or vascularstructures. In FIG. 102, the endoscope has been advanced along theligamentum flavum 6010 to the lateral recess 60136. “Safe zone” 6044designates the area in which a medical practitioner may resect, ablate,or otherwise modify tissue safely, under direct visualization. Thesecond barrel or lumen of the double barreled needle 60164 or endoscopemay be used as a working channel 6050, or to dispense a tissuemodification barrier or working barrier or backstop 60134.

In addition to the insertion of tools through the epidural needle 602,or through an adjacent working channel 6050, the same channels may beutilized to insert a barrier 60134, or “working backstop” 60134 (FIGS.103, 20 b, 21 b, 106, 107, 108), into the spine. In a further variationof the present invention, a flexible, flat, thin mechanical barrier(“working backstop”) 60134 is placed between the tissue to be resectedand adjacent vulnerable neural or vascular structures that are desiredto be left intact and uninjured. The barrier provides protection for thedura 6046, nerve root 6062, dorsal root ganglia, and/or vasculature, byproviding insulation and/or preventing direct contact between the toolsand these vulnerable structures during tissue manipulation, resection,abrasion, or remodeling. The protective barrier may be placed betweenthe needle based or endoscopically delivered tools and the dura 6046 inthe central spinal canal; in the lateral recess 60136; or between thetools and the neural and neurovascular structures within the neuralforamen 60110. The barrier 60134 may be placed through the neuralforamen 60110 anterior to the facet joint 6077, either anterior to theligamentum flavum 6010 (epidural space 6042) or within or posterior tothe ligamentum flavum 6010 (posterior to the epidural space 6042). Toolsthat may be used in conjunction with this barrier include, but are notlimited to, cautery devices (monopolar or bipolar), lasers (erbium,etc.), rasps, ronguers, graspers, burrs, sanders, drills, shavers, orprobes.

The barrier or backstop 60134 may be placed percutaneously via a needle602, endoscope 60132, or double barreled needle 60164. In addition toepidural endoscopy, image guidance may be combined with the use ofstraight, curved, or steerable guidewires for the proper placement ofthe barrier or backstop 60134. In an open surgical variation, thebarrier or backstop device 60134 may be placed through the surgicalincision.

The barrier 60134 may be synthesized from one of several possiblematerials, for example, it may be partially fabricated from a springsteel, Nitinol, polymers, or other memory material that will allow athin, flat barrier to be reconfigured into a more condensedconfiguration for passage through a straight needle [107 d], after whichit returns to its desired shape [107 c] upon exiting the needle 602. Thebarrier 60134, optionally, may be steerable.

As is illustrated in FIG. 108, correct anatomic placement of thebackstop device 60134 may be validated via monitored electrical neuralstimulation through the barrier device 60134. Electrical nervestimulation function may be added to the apparatus via dual conductiveelements, the first conductive element 60104 for neural stimulation andlocalization placed on the working side (e.g., on the surface) of thebackstop (or the tool used on the working side or the epidural endoscopetip), where tissue remodeling and resection will occur. The neuralstimulation delivery box 60114 can be attached to the ground electrode60116. In the example illustrated in FIG. 107, the working nervestimulator on the working side of the barrier may be integrated with therail 60128, through which nerve stimulation may be tested before slidingthe tool or sleeve over the rail for tissue modification. A conductiveelement (e.g., for neural stimulation) may also be placed on thenon-working side of the backstop 60130. To gain accuracy in neurallocalization, the stimulation leads on the device are separated byinsulation material within the backstop material.

The patient may be kept awake and responsive throughout this procedure,with no neuraxial anesthetics and no systemic analgesia. In this manner,the medical practitioner may, through verbal questioning, elicitresponses from the patient in order to ensure that any severe pain thatwould accompany undue pressure on the nerve root 6062 during placementof the tissue modification device and/or during tissue removal orremodeling is immediately recognized prior to nerve injury.Alternatively, for a deeply sedated patient, or one under generalanesthesia, nerve stimulation may be monitored via SSEPs or SEPs;visually (motor movement of extremities); via MEPs; and/or via EMG(motor stimulation). In one embodiment of the device, one might use acalibrated sensor, combined with computer analysis, to accuratelyquantify neural stimulation at different locations, in order to moreaccurately localize neural structures.

As is illustrated in FIG. 108, there should be no nerve root 6062 ordorsal root ganglion stimulation in the exact location where tissuealteration is intended to take place, when one sends appropriate smallelectrical current through an insulated electrode that is located on theworking side of an insulated working barrier, prior to tissuemodification tool placement. Correct neural location, relative to thetissue modification tools and barrier may further be ensured by theaddition of focused neural stimulation functionality to accompanyingsurgical instruments. For example, tools used for probing, tissueresection, tissue cauterization, thermal treatment, tissue lasering,tissue manipulation, tissue retraction, and tissue abrasion may containconductive elements for neural localization 60104. The nerve stimulationcapabilities may be used to ensure that the neural elements are not indangerous proximity, or they may be used to assist with more conciseneural localization. For instance, a probe fitted with neuralstimulation capabilities in its tip may be used to identify neuralstructures, through monitoring of sensory or motor stimulation. However,electrical stimulation on the non-working surface of the workingbarrier, which is in direct or indirect contact with neural structures,should result in motor and/or sensory action potentials, which may bemonitored as described above, thereby providing a positive control andassurance of proper barrier placement. For added safety, a surgicaldevice may be designed to automatically stimulate before or duringresection, and may even be designed to automatically block resectionwhen nerve stimulation has been sensed.

In a preferred variation, impinging spinal tissue is removed usingtissue abrasion apparatus and method. Variations of the apparatus andmethod may be utilized during an open surgical procedure(s); during anendoscopic surgical procedure(s); or via a percutaneous (needledelivered) surgical approach. Use of a needle-based posteriorinterlaminar or interspinous approach, a posterior-lateralneuroforaminal approach or a minimally-invasive surgical approach forplacement of the neuroforaminal abrasive tissue removal device avoidsunnecessary tissue resection and minimizes tissue injury. In addition,further embodiments of the device include nerve stimulation andmonitoring capabilities, which, when added to a spinal tissue alterationdevice, may enable the surgeon to more safely perform the procedure.

FIG. 109 shows the needle tip anterior to the ligamentum flavum 6010,but still posterior to the dura 6046 in the posterior epidural space6042. FIG. 110 illustrates a preferred method of cannulating the neuralforamina, where a blunt, curved needle composed of memory material 6016is passed through the straight epidural needle 602 (alternatively, astiff epidural catheter 6024, or steerable guidewire may be insertedthrough the needle for this step). The curved needle 6016 is flexibleenough to be passed through the straight epidural needle 602, but ismade of a memory material that returns it to its curved configurationupon when it is passed into tissue. The second needle 6018(alternatively, a steerable, stiff catheter, needle or guidewire), isadvanced through the epidural space 6042, possibly passing through aportion of the ligamentum flavum 6010, towards and then through theipsilateral or contralateral neural foramen 60110. The surgeon may useany combination of tactile feel, image guidance, direct visualization,and/or fiberoptic visualization to ensure that the curved element 6016is driven through the neural foramen 60110, anterior to the facet(zygapophysial) joint complex 6012, but posterior to the nerve root 6062or ganglion. Once the curved element is in position through the neuralforamen 60110, the surgeon subsequently passes a smaller gauge straightand sharp flexible wire 604 (or needle), as in FIG. 111 through thelumen of the larger curved needle that is in position through the neuralforamen 60110, until it exits into the tissue lateral to the neuralforamen 60110 (FIG. 111). This straight wire 604 or straight needleexits the curved element with its tip facing in a posterior orposterior-lateral direction. It is advanced further in this direction,passing to, and then through the skin of the patient's back 6070, as inFIG. 111.

Studies and tests may be performed to ensure that the transforaminallyplaced apparatus has been properly positioned between the nerve root6062 or ganglia and the facet joint complex 6012. For example, imagingof the abrasion element and spinal anatomy (fluoroscopic or otherimaging modalities); monitored neural stimulation through the apparatus;or direct (endoscopic or open) visualization may be utilized.

After proper placement has been confirmed, the curved element 6016 thatwas used to initially cannulate the neural foramen 60110 is removed, bypulling it back out of the hub of the epidural needle 602, leaving thetransforaminal wire 604 in place, as illustrated in FIG. 112. Next theepidural needle 602 may also be removed, if desired, again leaving thewire 604 in its position, through the neural foramen 60110. As shown,both ends of the element remain external to the patient, having exitedthe skin (percutaneous procedure) or exited the tissue through thesurgical wound (open procedure).

With the wire in position through the neural foramina, there aremultiple possible methods for replacing the wire with the abrasionapparatus. One method is illustrated in FIGS. 127-129, where the wire604 is used to pull into position the abrasion element 6014; theabrasion element sleeve or cover 606; or the abrasion element 6014 andcover 606 together, as is described in greater detail below.Alternatively, as shown in FIGS. 113 and 114, separate protectivesleeves or covers 606 may be passed over both the proximal and distalends of the transforaminal wire 604. Each sleeve or cover may beadvanced to the neural foramen 60110. Next, the neuroforaminally placedwire 604 is connected distally, or proximally, to the abrasive element6014, with an abrasive surface on one side. The abrasive element 6014,connected by one end to the transforaminal wire 604, is pulled throughthe neural foramen 60110, and through the protective sheaths or covers606, as in FIGS. 115 and 116, until the abrasive element 6014 hascompletely replaced the initially placed wire 604 (or needle). Passageof a tissue dilator over the transforaminal wire 604 or needle, may behelpful, either before or after placement of the sleeve. Protectivesleeve(s) 606 illustratively are disposed over both ends of thetransforaminal wire 604, in order to protect non-surgical tissues fromthe abrasive or cutting portion of the device, when it is pulled intoplace. Alternatively, a protective abrasive element sleeve 6098, whichmay be expandable, as illustrated in FIG. 167, may be attached to theend of the wire and pulled through the neural foramina, therebyreplacing the initial transforaminally placed element. The abrasiveelement sleeve 6098 covers the abrasive element in tissue and is aconduit for insertion and exchange of abrasive elements.

In an alternative preferred embodiment, the abrasive element 6014 ispositioned within the protective sleeve cover 606, before or afterplacement of the abrasive element in position through the neuralforamina. Please note that the terms “protective sleeve” and “protectivecover” are used interchangeably in these descriptions of severalexamples of the apparatus and methods for protecting vulnerable tissuefrom the abrasion apparatus. Embodiments of the protective methods andapparatus are illustrated in FIGS. 166-169. With the abrasive element6014 already inside the protective apparatus 606 or 6096, with orwithout an opening over the abrasive surface where tissue abrasion is tobe performed the protective covering, with the abrasive apparatusalready inserted within it, may be connected to one end of the needle orguidewire that remains in place through the neural foramen 60110. Inthis preferred method, the combined protective sleeve and 606 theabrasive element 6014 are then pulled simultaneously through the neuralforamen 60110, by pulling from the opposite end of the preliminarilyplaced neuroforaminal element, while it is removed. A conductive element6090 for neural stimulation can be on the working side of the apparatus.

Once the abrasion apparatus has been properly positioned through theneural foramina, with its protective cover in place, it is ready to betested to ensure it has been properly located. The apparatus maysubsequently be utilized for tissue abrasion, tissue removal, and tissueremodeling, as will be described in detail below. Before describingtissue modification in further detail, however, we will describealternative approaches for placement of the abrasion device intoposition through the neural foramina.

Referring now to FIGS. 117-120, a variation of the method and apparatusof FIGS. 109-116 is described comprising an alternative approach forplacement of the tissue modification device, wherein the apparatus 6014is placed from the lateral side of the neural foramen 60110. As seen inFIG. 117, a steerable or needle wire 6018 is placed through the neuralforamina 60110 from the lateral towards the medial side of the foramen60110. This lateral to medial neuroforaminal approach may begin with acurved, blunt wire through a straight needle (as described in theprevious technique), or using a curved needle technique, a steerableguidewire technique, a needle-through-a-needle technique, or commonvariations thereof. FIG. 120 illustrates that the protective sleeve 606or cover can have a neural barrier portion 608 for the abrasion element.While a loss of resistance technique is not as helpful with thistransforaminal approach to the epidural space 6042, as it was in thepreviously described posterior approach to the epidural space 6042, themethod is, in many other aspects, otherwise similar to the methodillustrated in FIGS. 109-116.

With reference to FIGS. 121 a-e, another variation of the method andapparatus of FIGS. 109-116 is described. In FIG. 37 a, the apparatus6020 is placed from an interlaminar; a translaminar, interspinous; or atransforaminal insertion, illustratively via a paramedian, ipsilateralapproach. A lateral to medial transforaminal approach with the same typeof apparatus may alternatively be used. The blunt or rounded distal tipof apparatus 6020 optionally may be somewhat sharper, to facilitateplacement. The apparatus 6020 may be preceded by a guidewire, a dilator,or a needle introducer (possibly with or followed by an expandablesheath). This variation of the apparatus and method, as seen in FIG. 37b, contains a rigid, curved wire or needle 6022, which may be steerable,which is driven from the tip of the apparatus 6020, laterally throughthe neural foramen 60110 and then posteriorly, around the facet jointcomplex 6012 and back towards apparatus 6020, where the needle may bereceived once again by the apparatus. Arrow 6026 in FIG. 37 dillustrates the direction of movement of the abrasive element. FIG. 122provides a cross section through apparatus 6020 that illustrates anexemplary geometry for the apparatus comprising a feature thatfacilitates receiving of the distal end of the needle or rigid guidewireback within the apparatus. Alternative geometries will be apparent. Oncereceived back within apparatus 6020, the wire 6022 completely encirclesthe facet joint 6012, as in FIG. 121 c, d. In FIGS. 121 d, 122, and 123,guidewire 6022 has been replaced by tissue abrasion device 6032, e.g., abelt, strap or ribbon, preferably within a protective sheath or cover,with the abrasive surface of the device in contact with theanterior-medial facet complex. Apparatus 6020 is pulled back, bringingthe working surface (exposed abrasive portion) of the instrument intofirm contact with operator controlled pressure against the surface fromwhich tissue removal will occur. Neuroforaminal enlargement begins withthe movement of the abrasive surface 6030 against the anterior andmedial portion of the facet complex 6012, in the lateral recess andneural foramen 60110. The abrasive surface 6030 can be of an abrasiveelement in an electromechanical abrasion device.

With reference to FIG. 122, an enlarged view of the mechanical portionof apparatus 6020 is described. An abrasive surface 6030 is disposedalong the inside side of tissue abrasion element. The abrasion devicemay be actuated, e.g., via rotation of a gear 60106 within the apparatus6020. The gear or knob 60106 engages with the abrasive element, and isturned to provide movement of the abrasive element within the apparatus.Debris may be captured within apparatus 6020, and stored in the shaftand/or handle 6068, or removed continuously during the procedure. Thedebris can be sent in the direction of arrow 60180 for removal orstorage.

Referring now to FIG. 123, a variation of the apparatus of FIG. 122 isdescribed comprising an additional protective cover 6032 that covers oneor more sides of the abrasive elements 6014 of the device 6020 in allregions except for the area covering the tissue where abrasion is totake place. This cover may contain a conductive element in order toenable nerve stimulation 60130 and/or to facilitate neural localization60104. Nerve stimulation capabilities may be present on the internalabrasive surface 6030 of device abrasive element 6014, and/or on theexternal side (non-tissue abrading) of the device, as an added safetymeasure. For example, the user may send an electric impulse through aconductive element within the back-side (external surface) of thedevice, expecting to achieve neural stimulation when the device is inplace through the neural foramina, while neural stimulation should notbe achievable with a similar electrical impulse conducted across aportion of the abrasive side of the device. In this manner, informationfrom monitoring the nerve stimulation may ensure proper placement of theabrasion device and reduce a risk of inadvertent neural or perineuralvascular abrasion.

In FIG. 124, straight wire or needle 604 is driven through curved needle6016 disposed in working channel 6050 of double barrel epidural needle60164. This straight wire or needle is advanced until it has penetratedthrough the skin and out of the patient's body. The straight wirepreferably has a sharp tip. In FIG. 125, the curved needle 6016 has beenwithdrawn from working channel 6050, leaving straight wire or needle 604in place. Then, as seen in FIG. 126, the epidural needle 602 and workingchannel may be withdrawn from the patient, or, in an alternativeembodiment (FIG. 98 b), when using a detachable working channel 6050,the working channel alone may be withdrawn from the patient, leavingstraight wire 604 in place. In FIG. 127, straight wire 604 has beenhooked to abrasion device 6014 and/or the abrasion device's protectivesleeve 606. In FIG. 128, the abrasion device 6014 and/or the device'sprotective sleeve are pulled into position by wire 604 as the wire isremoved. In FIG. 129, wire 604 has been completely removed, and theabrasion device 6014 and its protective sleeve 606 are properlypositioned for tissue resection, anterior to the facet 6012 andligamentum flavum 6010.

In an open surgical variation, the abrasive element 6014 and its cover606 may be placed through the surgical incision, from a interlaminar,translaminar, or neuroforaminal approach. Visualization and placementmay be aided via partial or complete laminectomy, facetectomy, orligamentectomy. Methods for threading the neural foramina include, butare not limited to the use of a wire, blunt needle, probe, endoscope, orsuture. After spinal neuroforaminal placement, the abrasion device 6014is used to selectively remove tissues that impinge on the neurovascularstructures within the lateral recess 60108 and neural foramen 60110, onthe anterior side of the facet joint 6012. In an open approach, as witha percutaneous approach, the device may be inserted through a needle,optionally under image guidance or with the aid of an epiduralendoscope. Once placed through the neural foramina 60110 of the spine,around the anterior border of the facet joint 6012, and anterior to theligamentum flavum 6010, the medical practitioner may enlarge the lateralrecess and neural foramina via frictional abrasion, i.e., by sliding theabrasive surface across the tissue to be resected (e.g., far lateralligamentum flavum 6010, anterior and medial facet, osteophytes). Theabrasion device alternatively or additionally may be placed through theneural foramen 60110 anterior to the facet joint 6012, but through orposterior to the ligamentum flavum 6010. The medical practitionercontrols the force and speed of the abrasive surface against the tissueto be removed, while optional protective covers, tubes or sleeves 606help limit the area exposed to the abrasive element for treatment.

Referring now to FIGS. 130-145, a variation of the method and apparatusof FIGS. 124-129 is described, comprising another preferred approach forplacement of the abrasion device. This series begins with FIG. 130, inwhich a double lumen, blunt tipped, epidural device 6084, has alreadybeen advanced to the lateral recess 60108, using a technique similar toFIG. 102. Next, FIG. 131 shows a curved flexible needle 6016, preferablywith an atraumatic tip, that has been advanced, via the working channel6050 (FIG. 99), through the neural foramina 60110. FIG. 132 illustratesthreading of the straight, flexible, sharp tipped wire 604 a through thecurved needle 6016, and advanced posteriorly until it exits the skin ofthe back 6070. In FIG. 133, the curved needle has been withdrawn,leaving the straight wire 604 a in place. In FIG. 134, the double lumenepidural apparatus 6084 is slightly withdrawn, from the patient, so thatthe working channel 6050 is directed towards the medial side of thefacet complex 6012. FIG. 135 shows the curved needle 6016 advancedthrough the working channel again, adjacent to the first wire 604 a,this time advancing the same or a different curved, flexible needle6016, towards the opposite side of the facet complex 6012. FIG. 136shows where a second straight flexible wire 604 b is advanced throughthe second placement of a curved needle 6016, this time on the medialside of the facet joint. The second sharp, flexible, straight wire 604 bis threaded through this second curved needle, and subsequently advancedposteriorly, until the sharp tip of the wire 604 b exits the skin. FIG.137 next shows both the curved needles and the double lumen apparatusremoved, leaving the wires 604 a and 604 b in place. FIG. 138 shows thatboth wires have been attached to the two ends of the abrasive elementand/or the cover 6032 of the abrasive element. Alternatively, the twowires 604 a and 604 b may be opposite ends of the same continuous wire,with the cover 6032 for the abrasive element already placed over themid-portion of the wire 604. Alternatively, the abrasive element 6014may already have been placed inside said cover 6032, and attached ateach end to the wires 604 a and 604 b. FIGS. 139 and 140 show the twowires 604 a and 604 b pulled and bringing the abrasive element cover,possibly with the abrasive element 6014 already placed inside said cover6032, into position through the neural foramina. FIG. 57 illustrates thestep that follows placement of the abrasion element cover alone. In FIG.57, with the wire in place inside the abrasion element cover 606, theabrasive element 6014 is now seen to have been attached to the end ofthe wire. Subsequently, the cover 6032 is held open at each end by agrasping device, which also holds the cover under tension against thetissue to be abraded. With the cover anchored thus, the abrasive elementis pulled into place by the wire, replacing the wire, as has occurredfor FIGS. 142 and 143. With the abrasive element in position and theabrasive element cover tightly held open and against the tissue to beabraded, the abrasion element 6014 may be pulled back and forth, undertension, against the tissue to be abraded, as in FIG. 143.Alternatively, the abrasive element may be pulled in a single directionacross the tissue to be abraded. FIG. 144 illustrates the coverfollowing removal of the abrasive element. Said cover may remain inplaced as a compression bandage 60168, under tension against the freshlyabraded surface, in order to promote hemostasis, promote tissueremodeling, and trap debris post operatively. The compression bandage60168 can be a percutaneous retention and compression dressing or tissueremodeling strap, or a retention strap or belt.

A nerve stimulator may be incorporated into the abrasive surface of theabrasive element, and/or incorporated into the protective cover 6088 orsheath for the abrasive element, in order to verify correct placementand enhance safety by allowing the medical practitioner to ensure thatneural tissue is not subject to inadvertent abrasion. FIG. 145illustrates a neural stimulation apparatus. FIG. 145 also illustrates anabrasion element 6014, disposed inside of a sheath or cover 606, andheld in place by tension retaining elements 60112 (shown in FIG. 144).The skin anchor 60112 for the abrasive element cover or sheath can holdthe cover under tension, allowing the abrasive element to be movedfreely within. The stimulation apparatus 60114 (e.g., the neuralstimulation delivery box) delivers a small electrical current throughthe working surface and/or the non-working surface (backside) of eitherthe tools used in the epidural space 6042, the abrasive element, and/orthe protective cover of the abrasive element. Preferably, one electrode,or wire 60120 to the electrode, would be connected to each side(abrasive and non-abrasive) of the entire device and sheath complex,along the full distance where tissue abrasion is planned to occur, inthe lateral recess, central canal, or neural foramen 60110. Neuralstimulation may be monitored via verbal response to stimulation in anawake or lightly sedated patient, or SSEP, MEP, EMG, or motor evokedmuscular movement in an asleep or sedated patient. One possiblemechanism for avoiding inadvertent neural damage may be to ensure thatthere is no neural stimulation when stimulating the working surface ofthe device. A positive control should be obtainable in the lateralrecess and neural foramen 60110, when stimulating the non workingsurface (back side) of the device or, preferably, the backside of thedevice cover or sheath 60172 (e.g., first portion of locking mechanism).

After the abrasion element, and possibly its protective sheath or cover[603, 6049, 6050], have been placed through the neural foramina 60110the abrasive surface is brought into firm contact with the tissue to beabraded by pulling tension simultaneously on each end of the abrasionelement. When both ends of the abrasive element 6014 are pulledsimultaneously, the abrasive surface of the device is brought undertension and into firm contact with the impinging spinal tissue on theanterior and medial sides of the facet joint complex 6012. Subsequently,one end of the abrasive element is pulled more forcefully than theother, sliding the abrasive surface is across the target tissue. Whenone end of the abrasive element is pulled with more force than theother, the ribbon moves in the direction of the stronger pull, while thelesser pull on the opposite end maintains force and creates frictionwith movement between the abrasive surface and the tissue to beresected. When the optional protective cover 606 or sheath is provided,both of its ends of the are, in one variation, pulled under traction andanchored in place, such that the abrasive element 6014 may be pulled ineither or both directions through the cover 606 or sheath withoutsignificant friction against and/or without causing trauma to adjacenttissues.

Alternatively, the abrasive element 6014 may be pulled in a singledirection across the tissue. The abrasive belt, strap or ribbon may be asingle length, pulled alternately in each direction, or it may bedispensed from a spool, as in FIG. 62 a, or from a reel to reelconfiguration, as in FIG. 62 b, and pulled in both directions or pulledin a single direction, across the tissue to be abraded. An alternativevariation of the apparatus and method utilize an electromechanical, beltdriven abrasive tool, an example of which was described previously inFIGS. 122 and 123.

In one variation of the invention, a tissue retention or compressiondressing (FIGS. 144, 154, 156) method and apparatus are utilizedimmediately following the tissue removal, ablation and remodelingprocedures described previously. For example, following neuroforaminaland lateral recess enlargement, it may be advantageous to leave, as asurgical dressing, a thin flat element 60150 pulled tightly against theresected, abraded, or remodeled tissue surface (e.g., around the facetcomplex 6012). The neuroforaminal compression element can be placedaround the facet complex. It is expected that a compression dressing ofthis nature will enhance hemostasis, promote healing and promotesubsequent tissue remodeling with the neural foramen 60110 widely open.Furthermore, the surgical dressing 60150 would provide a barrier to traptissue debris away from neural or neurovascular structures, whileproviding an optional technique for delivering medication, possibly as adepot, to the operative site. The dressing 60150 would also present asmooth surface towards the nerve root 6062 in the immediatepost-operative period.

As in FIG. 144, this neuroforaminal compression dressing may bepercutaneously held tightly in place against the resected, abraded, orotherwise remodeled surface (e.g., zygapophysial (facet) joint) 6077. Incertain embodiments, the compression dressing may be eitherpercutaneously removable (as shown in FIGS. 144 and 154), either bypulling the dressing through the neural foramen 60110, or by theinclusion of a biodegradable central component of the dressing, suchthat the two ends may be removed, with the dressing separating at itsbiodegradable portion in the middle. Other variations such a compressiondressing include a totally implanted and completely biodegradabledressing, as illustrated in FIG. 72 a or b. FIG. 72 a also illustratesthe transverse processes.

FIGS. 130-140 and 144, and FIGS. 147-154 illustrate midline orparamedian approaches to percutaneous placement of a neuroforaminalcompression device (e.g., percutaneous retention compression dressing ortissue remodeling strap) 60155 that is wrapped around the facet complex6012 and retracts the posterior aspect of the neural foramina,effectively dilating the space available for the neural and vascularstructures. FIGS. 67 a and b illustrate the first steps in a posteriorlateral neuroforaminal approach to placement of a compression element(subsequent steps would share similarities with the approach illustratedin FIGS. 130-140 and 144). A grasper, loop or hook 60146 can be forgrabbing an end of the guidewire.

An additional embodiment of the method and apparatus may combine boththe working backstop 60134 and the compression element 60150, 60155, asillustrated in FIGS. 157 and 158. In these illustrations, thecompression element 60150, 60155 serves to keep the working barrier60134 in proper position. Subsequently, image guidance may be used toguide tools used in open or percutaneous procedural approaches toneuroforaminal and lateral recess enlargement. The example in FIG. 158illustrates an image guided drill 60176 removing a portion of theimpinging facet complex 6012. With the barrier in place, possiblyfurther aided by neural stimulation/localization capabilities, selectiveand safe tissue removal may be more readily performed.

FIGS. 159-162 illustrate some of the compression element embodiments60150, 60155. FIG. 160 also contains an area (e.g., a drug depot in aretention strap or compression dressing) 60162 for storage ofmedications for delivery to the tissue retracted by the compressionelement 60150, 60155. The compression element can have a lockingmechanism that can have a first portion 60172 that can insert through asecond portion. The compression element can have a locking mechanismthat can have a second portion 60174 that can receive a first portion60172.

FIGS. 163 and 164 demonstrate additional methods and apparatus forenlargement of the central spinal canal and lateral recess, byretracting the posterior spinal anatomy, in particular the ligamentumflavum 6010 (FIGS. 163 and 164 illustrate translaminar ligamentum 6010retraction), in a further posterior direction, away from the dura 6046,cauda equina 60140, nerve roots 6062, and dorsal root ganglia. Such adevice would both serve both to retract the spinal tissue posteriorly,and to prevent the posterior elements, particularly the ligamentumflavum 6010, from buckling anteriorly 60138 into the spinal canal orlateral recess. FIG. 163 illustrates an apparatus with an anchor 60126anterior to or within the ligamentum flavum 6010, a second (e.g.,laminar) anchor 60166 posterior to the lamina 60122 (e.g., for posteriorretention) and a mechanism for maintaining tension in order to retractthe tissues posteriorly, towards the lamina 60122. FIG. 164 illustratesa rivet type device that is placed through a hole that has been drilledthrough the lamina 60122. Such a rivet has an anchor 60126 placedanterior to the ligamentum flavum 6010, which is retracted posteriorlyin order to enlarge the central spinal canal and/or lateral recess.Spinal endoscopy may be used as a tool to place a ligamentum flavum 6010retraction system, or in order to confirm that correct placement andefficacy has been achieved.

Most of the safety issues related to the methods and apparatus describedherein are similar to those associated with any surgical procedure,e.g., infection and/or bleeding. Some safety issues are more specific tosurgery in and around the spine or spinal cord, and are therefore givenspecial consideration below. These generally relate to spinal nerveinjury. Morbidity could result from instruments inadvertently passedthrough the dura mater 6046, and creating a cerebrospinal fluid leakand/or damaging the cauda equina 60140 (below T12-L1) or spinal cord(above T12-L1) when entering the epidural space 6042. Potentiallytraumatized structures further include nerve roots 6062, adjacentvasculature, or dorsal root ganglia.

FIG. 165 are sagittal midline cryosections of the lumbar spine, providedcourtesy of Wolfgang Rauchning, Md., that demonstrate the ligamentumflavum 6010 protruding (“buckling”) anteriorly, a potential mechanismfor central or lateral recess neural or neurovascular impingement. Theligamentum flavum 6010 is a potential target for abrasive tissueresection using the herein described methods and apparatus.

FIGS. 166, 167, 168, 169, 171 illustrate preferred embodiments of theprotective cover or sheath for the abrasion element, in which theabrasive surface is covered 6098 and the backside of the abrasiveelement may also be shielded 6048, to prevent tissue damage in areaswhere tissue abrasion is not intended. The abrasive element's protectivecover 606 is ideally shaped to provide optimal protection of vulnerabletissues, at the same time maintaining both a very small profile, foreasy threading of the stenotic neural foramen 60110; and atraumaticedges (e.g. rounded), in order to prevent cutting of or trauma toneural, vascular or other tissue during placement, use or removal of thedevice. For example, in certain preferred embodiments, the abrasiondevice may be tubular (FIG. 166), with an opening over the tissue to beabraded; or may be flat (FIGS. 167, 168, 169, 171) with atraumaticrailings or tracks that facilitate passage of the abrasion element,abrasion surface cover, or other instruments. Side channels 6082 (e.g.,the edge of the backing for the abrasive element), through which theedges of the abrasion element may be maintained or held but are able toslide freely may be of an atraumatic shape. Said side channels may alsohold the protective cover 6094 for the abrasive side of the abrasionelement 6014. Note that neural stimulation and localization may beperformed through a conductive element 6086 in the back cover, the frontcover (e.g., a strap tension element 60170), or in the abrasive side ofthe abrasive element itself 6014. Both free ends of the device, as wellas the ends of the optional protective sheath or cover, are positionedexternal to the patient for manipulation by a medical practitioner.

FIG. 168 show a similar protective cover and abrasive elementconfiguration to that described in FIG. 167, this time with neuralstimulation element 6092 only illustrated in the non-abrasive (e.g.,non-working) side of the apparatus (e.g., protective cover). Inaddition, FIGS. 168 e and 168 f show that the abrasive element 6014 hasbeen replaced by an alternative element for drug deposition 6088 (e.g.,a drug depot strip for insertion into the compression strap, workingbackstop or barrier device; a retention strap or belt, or a compressionbridge), and/or to serve as part of the compression dressing, when theelements are left under tension against the abraded surface, after theoperative procedure.

FIG. 169 illustrate an additional similar embodiment of the abrasiveelement 6014 with protective covers 6094, 6096: the removable cover 6094for the abrasive (i.e., working) side of the of the abrasive element,and the protective working barrier 6096 (i.e., the working backstop) forthe abrasive element. This time, no neural stimulation elements areillustrated.

Referring now to FIGS. 170 and 171, cross sections through the abrasiveapparatus are illustrated. The abrasive element 6014 is seen, housedwithin the protective covers. As shown, the abrasion element may, forexample, be structured as a thin belt or ribbon, with an abrasive 60102and/or cutting surface 60100 on one of its sides. The cutting surface60100 can be an abrasive surface of the apparatus with a miniature bladedesign. The abrasive surface 60102 can be an abrasive surface of theapparatus with a sandpaper design. The abrasive element 607 may exist ina variety of shapes, ranging from flat to curved; from narrow to wide;and from a solid to perforated. The abrasive surface of the abrasiveelement may, in one variation, contain deep grooves 60118 orperforations for the transport, collection and removal of (tissue)debris away from the operative site. Alternatively, the pattern ofabrasive may be designed to control the direction and speed of movementof the surface across the tissue to be abraded (e.g. deep grooves 60118,at a diagonal to the edge of the straps, may be used to facilitatelateral movement of the abrasive element). The width and shape of theabrasive elements may also be varied, in further effort to control thearea of tissue to be resected. Finally, in one preferred variation, thesurgeon would begin with a coarser grade of abrasive material, in orderto gain more aggressive tissue removal. Sequential use of less and lessaggressive surfaces would serve to smooth the abraded tissue surface,with the aim of creating an atraumatic surface for contact withneurovascular structures.

Placement of a tissue abrasion device 6086 through protective sleeve(s)and 6048 into position for selective tissue removal, brings the abrasivesurface into contact with the tissue to be removed. A medicalpractitioner may remove tissue in contact with abrasive surface (FIGS.171 a, b, c) by applying a reciprocating or unidirectional motion to theends of device 6086 exterior to the patient. In one variation, a spoolor reel to reel configuration may be designed that begins with a coarsegrade of abrasive material, and progresses towards less abrasivematerials as the spool or reel unwinds.

In one variation, the device includes a compression dressing asillustrated in the percutaneous embodiment described above in FIGS. 144and 145. Following neuroforaminal and lateral recess enlargement, it maybe advantageous to leave, as a surgical dressing, a belt or ribbonpulled tightly against the abraded tissue surface. It is expected that acompression dressing will enhance hemostasis, promote healing andpromote subsequent tissue remodeling with the neural foramen 60110widely open. Furthermore, the surgical dressing would provide a barrierto trap tissue debris away from neural or neurovascular structures,while providing an optional technique for delivering medication,possibly as a depot, to the operative site. The dressing would alsopresent a smooth surface towards the nerve root 6062 in the immediatepost-operative period.

The neuroforaminal compression dressing may, in one preferredembodiment, comprise the optional protective sheath, percutaneously heldtightly in place against the abraded surface, after the abrasiveapparatus has been removed from its lumen, for a period of time.Alternatively or additionally, a separate percutaneously removablecompression dressing may be placed following tissue abrasion. Theabrasive material may be followed by a length of compression dressingmaterial on the same reel or spool, or a subsequent reel or spool.Alternatively, a compression dressing may be delivered through theneural foramen 60110 as a separate element. The compression element mayalso be used to deliver medications or other bioactive components (e.g.steroid, biodegradable adhesion barriers, etc.), to the surgical site.The compression dressing material may be, in one variation, partially orcompletely biodegradable. An entirely biodegradable compression dressingmay be placed tightly against the abraded surface, and left completelyimplanted following the procedure.

Whether placing the apparatus with an epidural needle 602; through theworking channel of an epidural needle e.g. 6050; with an epiduralendoscope; or during an open surgical procedure; image guidance may beused to facilitate safe and accurate placement. If the epidural needle602 has been replaced by, or converted to, an endoscope, directvisualization of the epidural space 6042 may be accomplished. In thiscase, as illustrated in FIGS. 172-183, the clear tip of the fiberopticscope will facilitate visualization through the fat present in theepidural space 6042. The fiberoptic cable may be rigid or flexible. Theendoscope fiberoptic cable tip may be straight or angled, with the flatsurface of its distal tip 6066 perpendicular (0°, for straight aheadviewing) or at an angle (e.g. 30°, 45°, or 60°). The cannula or portal(e.g., an epidural endoscope) may be closed at its tip or end 6076, asin FIGS. 172-183, covering and protecting the distal end of thefiberoptic cable with a clear tip 6074 which may be solid, fluid, or gasfilled, potentially sized and shaped to expand the area of viewingwithin the fat filled epidural space 6042. Additionally the endoscope or“needlescope” may contain an additional channel or space for infusion offluid into the epidural space 6042, in order to facilitatevisualization, to create a space for visualization, and/or to decreasebleeding by increasing pressure, towards or above venous pressure,within the viewing area.

FIGS. 172 through 183 illustrate several embodiments of closed tipportals for epidural fiberoptic visualization. Some description of theseportals may be found in the text above. Basically, the portals showseveral preferred variations of designs that enable visualizationthrough the fat that exists in the epidural space 6042. The clear tipsof the portals may be solid and clear, or may contain air or clearliquid. The volume of the tip creates a space for improved perspectiveduring visualization.

Referring now to FIG. 172, a hockey stick shaped portal facilitatessteering of the portal by rotation of the device. Such a design may beused with a flexible, partially flexible, or rigid fiberoptic element6064. Besides steering the portal tip, the fiberoptic element may berotated separately in order to direct visualization, when angled scopetips are used (e.g. 30°, 45°, 60°). Alternative embodiments, asillustrated in FIG. 176, may allow the flexible neck (i.e., tip) 6072 ofthe instrument (e.g., the clear tipped epidural endoscope portal) to besteered. FIGS. 178-180, 182, and 183 illustrate means of deliveringtools along with the epidural endoscopic portals. Finally, FIG. 181 showa couple of different shapes of the many possible variations that may behelpful in improving visualization and access to the central canal,lateral recesses, neural foramen 60110 and posterior annulus of thespine.

Many of the safety issues related to the methods and apparatus describedherein are similar to those associated with any surgical procedure,e.g., infection and/or bleeding. Some safety issues are more specific tosurgery in and around the spine or spinal cord, and are therefore givenspecial consideration below. These generally relate to spinal neural andneurovascular injury. Central Nervous System injury could result frominstruments inadvertently traumatizing the dura mater 6046 when enteringthe epidural space 6042, injuring the nerve root(s) 6062, the adjacentvasculature, or the dorsal root ganglion as the apparatus is advancedand utilized towards and through the neural foramen 60110.

Several techniques may be used to reduce a risk of dural, neural orneurovascular injury, including potentially traumatizing structuresincluding nerve roots 6062, adjacent vasculature, or dorsal rootganglia. For example, the tissue alteration (e.g., abrasion) devices maybe placed under direct visualization when utilizing an open surgicalapproach or technique. Likewise, image guidance may be provided duringplacement or to confirm correct placement. Candidate image guidancetechniques include fluoroscopy, fluoroscopy alone, fluoroscopy withadditional technology for triangulation and tracking of instruments(e.g. infrared, RF, etc.), MRI, CT, OCT, ultrasound, etc. Catheters orguidewires may include their own image guidance capabilities such ascatheter or guidewire-based image guidance, e.g., fiberopticvisualization, catheter-based ultrasound, catheter-based MRI, opticaltomography, etc. Alternatively or additionally, endoscopic visualizationmay be utilized (e.g. flexible fiberoptic endoscope as in Epiduroscope,or via rigid surgical endoscopes), during placement and/orpost-placement confirmation of correct placement.

In addition to epidural endoscopy, image guidance may be combined withthe use of straight, curved, or steerable guidewires for the properplacement of the neuroforaminal abrasive element. Placement may beachieved percutaneously or through a surgical incision. Such a devicemay be implanted as an adjunct to an open surgical procedure(s); as anadjunct to an endoscopic surgical procedure(s); or as a separate open,image-guided percutaneous or endoscopic surgical procedure. Percutaneousapproaches will enable the surgeon to perform the procedure under localanesthetic in awake or sedated patients, if desired. As discussed, nervestimulation and localization capabilities may be added to the device inorder to enable the surgeon to more safely perform the procedure in ananesthetized, but un-paralyzed patient.

It is expected that the apparatus and methods of the present inventionwill facilitate a minimally invasive approach to the selectiveelimination (e.g., alteration, ablation, removal) of pathological spinaltissue, thereby enabling symptomatic relief in patients suffering fromspinal stenosis. Spinal neural and neurovascular impingement causetremendous pain and disability, with symptoms that include back and legpain, weakness, and decreased sensation. Neural ischemia and injurycaused by compression and inflammation may result in a wide range ofsymptoms or degrees of nerve damage. Symptoms range in severity frommild to severe, and from intermittent to permanent. For example,neurogenic claudication, which is exacerbated by back extension (asoccurs when one stands erect and places the spine in extension), may bemild or severe. Symptoms of neurogenic claudication are usually improvedby changes in posture that lead to back flexion, such as sitting. Themost severe cases of spinal stenosis may lead to permanent neurologicaldamage, including the possibility of the development of cauda equinasyndrome.

Spine surgeons lack safe and effective techniques or tools to minimallyinvasively or percutaneously reduce neural and neurovascular impingementin the spine, while minimizing collateral tissue damage. It is expectedthat the apparatus and methods of the present invention may be utilizedfor lateral recess and neuroforaminal enlargement to provide adequatebone and soft tissue resection, while reducing unnecessary destructionof functional bone, ligament or muscle in order to gain access to thetissues to be resected or modified.

Because critical neural and neurovascular structures are in closeproximity to the areas where surgical manipulation, dissection,resection, ablation and remodeling would be therapeutically valuable inthe spine, safety at each step in the procedure is of criticalimportance in order to avoid disabling neurological damage to thepatient. For this reason, safety measures, such as working barriers andnerve localization via an integrated nerve stimulator, are described.

Although preferred illustrative embodiments of the present invention aredescribed hereinabove, it will be apparent to those skilled in the artthat various changes and modifications may be made thereto withoutdeparting from the invention. It is intended in the appended claims tocover all such changes and modifications that fall within the truespirit and scope of the invention.

Tissue Modification Barrier Devices and Methods

The present invention relates to methods and apparatus for modifyingtissue in a patient.

Many pathological conditions in the human body may be caused byenlargement, movement, displacement and/or a variety of other changes ofbodily tissue, causing the tissue to press against (or “impinge on”) oneor more otherwise normal tissues or organs. For example, a canceroustumor may press against an adjacent organ and adversely affect thefunctioning and/or the health of that organ. In other cases, bonygrowths (or “bone spurs”), arthritic changes in bone and/or soft tissue,redundant soft tissue, or other hypertrophic bone or soft tissueconditions may impinge on nearby nerve and/or vascular tissues andcompromise functioning of one or more nerves, reduce blood flow througha blood vessel, or both. Other examples of tissues which may grow ormove to press against adjacent tissues include ligaments, tendons,cysts, cartilage, scar tissue, blood vessels, adipose tissue, tumor,hematoma, and inflammatory tissue.

One specific example of a condition caused by tissue impingement isspinal stenosis. Spinal stenosis occurs when neural tissue and/orvascular tissue in the spine become impinged by one or more structurespressing against them (“neural and/or neurovascular impingement”),causing one or more symptoms. This impingement of tissue may occur inone or more of several different areas in the spine, such as in thecentral spinal canal (the vertical passage through which the spinal cordand cauda equina extends), the lateral recesses of the spinal canal, orone or more intervertebral foramina (the openings through which nerveroots branching from the spinal cord pass).

For explanatory purposes, FIG. 1 is offered to show an approximate topview of a vertebra (one of the bones of the spinal column) with thecauda equina (the horsetail-shaped bundle of nerves that extends fromthe base of the spinal cord through the central spinal canal) shown incross section and two nerve roots exiting the central spinal canal andextending through intervertebral foramina on either side of thevertebra. (FIG. 1 is not drawn to exact scale and is intended forexemplary purposes only. It should be emphasized here that the drawingfigures appended to this application are not intended to be preciselyanatomically correct and are provided for exemplary purposes tofacilitate description.) The spinal cord and cauda equina run verticallyalong the spine through the central spinal canal, while nerve rootsbranch off of the spinal cord and cauda equina between adjacentvertebrae and extend through the intervertebral foramina.

One common cause of spinal stenosis is buckling and thickening of theligamentum flavum (one of the ligaments attached to and connecting thevertebrae), as shown in FIG. 1. Buckling or thickening of the ligamentumflavum may impinge on one or more neurovascular structures, dorsal rootganglia, nerve roots and/or the spinal cord itself. Another common causeof neural and neurovascular compression within the spine is disease ofone or more of the intervertebral discs (the malleable discs betweenadjacent vertebrae), which may lead to collapse, bulging or herniationof the disc. In FIG. 1, an intervertebral disc is shown with threesolid-tipped arrows demonstrating how the disc might bulge or herniateinto the central spinal canal to impinge upon the spinal cord, caudaequina and/or individual nerve roots. Other causes of neural andneurovascular impingement in the spine include: hypertrophy of one ormore facet joints (also known as zygopophaseal joints, facet jointsprovide articulation between adjacent vertebrae—two vertebral facetsuperior articular processes are shown in FIG. 1); formation ofosteophytes (bony growths or “bone spurs”) on vertebrae;spondylolisthesis (sliding of one vertebra relative to an adjacentvertebra); and (facet joint) synovial cysts. Disc, bone, ligament orother tissue may impinge on the spinal cord, the cauda equina, branchingspinal nerves and/or blood vessels in the spine to cause loss offunction, ischemia (shortage of blood supply) and even permanent damageof neural or neurovascular tissue. In a patient, this may manifest aspain, impaired sensation and/or loss of strength or mobility.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% of adults aged 50 and older and is the most frequentreason cited for back surgery in patients aged 60 and older.Conservative approaches to the treatment of symptoms of spinal stenosisinclude systemic medications and physical therapy. Epidural steroidinjections may also be utilized, but they do not provide long lastingbenefits. When these approaches are inadequate, current treatment forspinal stenosis is generally limited to invasive surgical procedures toremove vertebral ligament, cartilage, bone spurs, synovial cysts,cartilage, and bone to provide increased room for neural andneurovascular tissue. The standard surgical procedure for spinalstenosis treatment includes laminectomy (complete removal of the lamina(see FIG. 1) of one or more vertebrae) or laminotomy (partial removal ofthe lamina), followed by removal (or “resection”) of the ligamentumflavum. In addition, the surgery often includes partial or occasionallycomplete facetectomy (removal of all or part of one or more facet jointsbetween vertebrae). In cases where a bulging intervertebral disccontributes to neural impingement, disc material may be removedsurgically in a discectomy procedure.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the effected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. In a spinal fusion procedure, the vertebrae are attached togetherwith some kind of support mechanism to prevent them from moving relativeto one another and to allow adjacent vertebral bones to fuse together.Unfortunately, a surgical spine fusion results in a loss of ability tomove the fused section of the back, diminishing the patient's range ofmotion and causing stress on the discs and facet joints of adjacentvertebral segments.

While laminectomy, facetectomy, discectomy, and spinal fusion frequentlyimprove symptoms of neural and neurovascular impingement in the shortterm, these procedures are highly invasive, diminish spinal function,drastically disrupt normal anatomy, and increase long-term morbidityabove levels seen in untreated patients.

Therefore, it would be desirable to have less invasive methods anddevices for addressing neural and neurovascular impingement in a spine.Ideally, methods and devices for addressing impingement in spine wouldtreat one or more target tissues while preventing unwanted effects onadjacent or nearby non-target tissues. Also ideally, such methods anddevices would be minimally invasive and reduce impingement withoutremoving significant amounts of vertebral bone, joint, or other spinalsupport structures, thereby avoiding the need for spinal fusion and,ideally, reducing the long-term morbidity levels resulting fromcurrently available surgical treatments. It may also be advantageous tohave less invasive methods and devices for modifying target tissues inparts of the body other than the spine while preventing modification ofnon-target tissues. At least some of these objectives will be met by thepresent invention.

Description of Background Art. Flexible wire saws and chain saws, suchas threadwire saws (T-saws) and Gigli saws, have been used since thelate 1800s to saw through or file/abrade bone and other tissue in thehuman body. See, for example, Brunori A et al., “Celebrating theCentenial (1894-1994): Leonardo Gigli and His Wire Saw,” J Neurosurg82:1086-1090, 1995. An example of one such saw is described in U.S. Pat.No. 8250, issued to P. A. Stohlmann on Nov. 28, 1876. A description ofusing a T-saw to cut vertebral bone is provided in Kawahara N et al.,“Recapping T-Saw Laminoplasty for Spinal Cord Tumors,” SPINE Volume 24,Number 13, pp. 1363-1370.

A method and apparatus for treating spinal stenosis is described in PCTPatent Application Pub. No. WO 01/08571. A surgical instrument forremoving cartilage from a knee cavity is described in U.S. Pat. No.3,835,859.

Methods, apparatus and systems for modifying tissue in a patient areprovided. Although the following description and accompanying drawingfigures generally focus on tissue modification in spine, in variousalternative embodiments any of a number of tissues in any of a number ofanatomical locations in a patient may be modified.

Referring to FIG. 184, in one embodiment a tissue modification device65102 may include an elongate body 65108 having a proximal portion 65107and a distal portion 65109, a handle 65104 with an actuator 65106coupled with proximal portion 65107, one or more tissue modifyingmembers 65110, and one or more protective surfaces 65112. In variousembodiments, some of which are described further below, modificationdevice 65102 may be introduced into an area for performing a treatment,such as a spine, using any of a number of different introductionmethods, devices and systems. In FIG. 184, for example, modificationdevice 65102 extends through an introducer device 65114 placed through afirst incision 65240 on the patient's back and into the central spinalcanal. Modification device 65102 is advanced along a guide member 65116,which extends through introducer member 65114, through theintervertebral foramen between two adjacent vertebrae (only part of onevertebra is shown in FIG. 184), and out a second (or “distal”) incision65242 on the back. In some embodiments, as shown, guide member has abeveled distal tip 65117 for facilitating advancement of guide member65116 through tissue.

Generally, tissue modification device 65102 may be advanced to aposition in the spine such that tissue modifying member 65110 facestarget tissue to be modified, such as buckled, thickened or otherwiseimpinging ligamentum flavum tissue as shown in FIG. 184. Modificationdevice 65102 is configured such that when tissue modifying member 65110faces the target tissue, protective surface(s) 65112 face non-targettissue. Protective surface 65112 may be simply a length of elongate body65108 or may have one or more protective features, such as a wideneddiameter, protective or lubricious coating, extendable barrier,drug-eluting coating or ports, or the like. In some instances,protective surface(s) 65112 may act as “non-tissue-modifying”surfaces,in that they may not substantially modify the non-target tissue. Inalternative embodiments, protective surface(s) 65112 may affectnon-target tissue by protecting it in some active way, such as byadministering one or more protective drugs, applying one or more formsof energy, providing a physical barrier, or the like.

In some embodiments, once tissue modification device 65102 is positionedsuch that tissue modifying member 65110 faces target tissue andprotective surface 65112 faces non-target tissue, an anchoring force maybe applied at or near distal portion 65109 of elongate body 65108,either inside or outside the patient's body. A tensioning force may alsobe applied at or near proximal portion 65107 of elongate body 65108,such as by pulling on handle 65104 (one-directional arrows), andactuator 65106 may be used (two-headed arrow) to activate tissuemodifying member(s) 65110 to modify target tissue. In the example shown,anchoring force is applied near distal portion 65109 by a user's hand65244, and handle 65104 is pulled proximally (arrows) to applytensioning force. In an alternative embodiment, hand 65244 may graspguide member 65116 at or near its distal portion 65117 and thus applyanchoring force to it, thus also applying anchoring force to elongatebody 65108. In one variation of such an embodiment, elongate body 65108or handle 65104 may optionally be adjustably clamped to guide member65116 to further enhance or facilitate application of anchoring force toelongate body 65108. Tissue modification via tissue modifying members65110 may include cutting, ablating, dissecting, repairing, reducingblood flow in, shrinking, shaving, burring, biting, remodeling,biopsying, debriding, lysing, debulking, sanding, filing, planing,heating, cooling, vaporizing, delivering a drug to, and/or retractingthe target tissue. Once tissue has been modified, tissue modificationdevice 65102 and any introducer devices 65114, guide members 65116 orother devices may be removed from the patient.

In various embodiments of the apparatus, tissue modifying member(s)65110 may be disposed along any suitable length of body 65108. In oneembodiment, for example, such as an embodiment of the device to be usedin a spinal treatment, tissue modifying members 65110 may be disposedalong a length of the device measuring no longer than 10 cm, andpreferably no more than 6 cm, and even more preferably no more than 3cm. In various embodiments, tissue modifying member(s) 65110 may includea rongeur, a curette, a scalpel, one or more cutting blades, a scissors,a forceps, a probe, a rasp, a file, an abrasive element, one or moresmall planes, an electrosurgical device, a bipolar electrode, a unipolarelectrode, a thermal electrode, a rotary powered mechanical shaver, areciprocating powered mechanical shaver, a powered mechanical burr, alaser, an ultrasound crystal, a cryogenic probe, a pressurized waterjet, a drug dispensing element, a needle, a needle electrode, or somecombination thereof. In various embodiments, all tissue modifyingmembers 65110 may be mobile relative to the elongate body, all may bestatic, or some may be mobile and some may be static. These and otheraspects and embodiments are described further below.

Turning now to FIG. 185A-185I, more detailed figures of one embodimentof tissue modification device 65102 are shown. Referring to FIG. 185A,tissue modification device 65102 may include elongate body 65108 havingproximal portion 65107 and distal portion 65109, a window 65111 disposedalong elongate body 65108, two tissue modifying blades 65110 exposedthrough window 65111, and handle 65104 with actuator 65106 coupled withproximal portion 65107. In the embodiment shown, the tissue modifyingmembers comprise blades 65110, although in alternative embodiments othertissue modifying members may be added or substituted.

In various embodiments, elongate body 65108 may have any number ofdimensions, shapes, profiles and amounts of flexibility. For example,distal portion 65109 is shown having a curved shape to demonstrate thatat least a portion of elongate body 65108 may be flexible. In variousembodiments, elongate body 65108 may have one or more of a round, ovoid,ellipsoid, flat, cambered flat, rectangular, square, triangular,symmetric or asymmetric cross-sectional shape. As shown in FIGS. 185Cand 185D, in the pictured embodiment, elongate body 65108 has arelatively flat configuration, which may facilitate placement of body65108 between target and non-target tissues. Distal portion 65109 ofbody 65108 may be tapered, to facilitate its passage into or throughnarrow spaces as well as through small incisions on a patient's skin.Body 65108 may also include a slightly widened portion around the areaof window 65111 and blades. In one embodiment, such as an embodimentused for modifying tissue in a spine, body 65108 may have a smallprofile, such as having a height of not more than 6510 mm at any pointalong its length and a width of not more than 20 mm at any point alongits length, or more preferably a height not more than 5 mm at any pointalong its length and a width of not more than 6510 mm at any point alongits length, or even more preferably a height not more than 2 mm at anypoint along its length and a width of not more than 4 mm at any pointalong its length. Body 65108 may be long enough to extend through afirst incision on a patient, between target and non-target tissue, andout a second incision on a patient. Alternatively, body 65108 may belong enough to extend through a first incision, between the target andnon-target tissue, and to an anchoring location within the patient. Inanother alternative embodiment, body 65108 may be long enough to extendthrough a first incision, between the target and non-target tissue, to alocation nearby but distal to the target tissue within the patient, withsome portion of tissue modification device 65102 anchored to guidemember 65116. In some embodiments, elongate body 65108 includes at leastone feature for allowing passage of the body over a guidewire or otherguide member or to allow passage of one or more guide members over orthrough body 65108. For example, in various embodiments body 65108 mayinclude one or more guidewire lumens, rails, tracks, lengthwiseimpressions or some combination thereof.

In one embodiment, elongate body 65108 is predominantly flexible alongits length and comprises any suitable flexible material, such as thin,flexible metals, plastics, fabrics or the like. In some embodiments, itmay be advantageous to include one or more rigid sections in elongatebody 65108, such as to impart pushability to a portion of body 65108 orto facilitate application of force to tissue modification members 65110without causing unwanted bending or kinking of elongate body 65108. Insuch embodiments, rigidity may be conferred by using additionalmaterials in body 65108 or by making the rigid portions thicker or wideror of a different shape.

Handle 65104 may have any suitable configuration according to variousembodiments. Similarly, actuator 65106 may include any of a number ofactuation devices in various embodiments. In the embodiment shown inFIG. 185A, actuator 65106 comprises a trigger or moving handle portion,which is grasped by a user and pulled or squeezed toward handle 65104 tobring blades 65110 together to cut tissue. In an alternative embodiment,actuator 65106 instead may include a switch or button for activating aradiofrequency surgical ablation tissue modifying member. In yet anotherembodiment, actuator 65106 may include a combination trigger and switch,one or more pull wires, any suitable form of lever and/or somecombination thereof.

FIGS. 185B-185D show in greater detail a portion of tissue modificationdevice 65102. In these figures, window 65111 and blades 65110 are moreclearly seen. In one embodiment, at least a portion of elongate body65108 and blades 65110 may have a slightly curved configuration. Inalternative embodiments, at least a portion of elongate body 65108 andblades 65110 may be flat. In other alternative embodiments, tissuemodification members such as blades 65110 may be proud to elongate body65108.

Blades 65110 include a distal 65110 a and a proximal blade 65110 b thatreside at the distal and proximal edges, respectively, of window 65111of elongate body 65108. Window 65111 of body 65108 may accommodate bothsoft and hard tissue when the device is forcibly applied to the surfaceof a target tissue site. The top view of the distal portion of elongatebody 65108, shown in FIG. 185C, depicts the angled edges of distal blade65110 a and proximal blade 65110 b, which facilitate shearing of targettissue. In alternative embodiments, blades 65110 may have any of anumber of alternative shapes and configurations. The distal portion ofbody 65108 may have a very low profile (height compared to width), asshown in side view FIG. 185D, where only blades 65110 protrude from thetop surface of the elongate body 65108. In one embodiment, also as shownin FIG. 185D, a guidewire tube 65120 (or lumen) may extend from (or becoupled with) a lower surface of elongate body 65108. The lower surfaceof elongate body 65108 is an example of a protective ornon-tissue-modifying surface.

In one embodiment, distal blade 65110 a is coupled with two pull-wires65118, as seen in FIGS. 185C, 185E and 185F. Pull-wires 65118 coupled toand translated by actuator 65106 on handle 65104 may be used to drivedistal blade 65110 a proximally to contact the cutting edge of proximalblade 65110 b, thus cutting tissue. Other alternative mechanisms fordriving blades 65110, such as gears, ribbons or belts, magnets,electrically powered, shape memory alloy, electro magnetic solenoidsand/or the like, coupled to suitable actuators, may be used inalternative embodiments. As mentioned, in one embodiment distal blade65110 a and/or proximal blade 65110 b may have an outwardly curvilinearshape along its cutting edge. Alternatively, distal blade 65110 a mayhave a different blade shape, including flat, rectilinear, v-shaped, andinwardly curvilinear (concave vs. convex). The cutting edge of eitherblade 65110 may have a sharp edge formed by a simple bevel or chamfer.Alternatively or in addition, a cutting edge may have tooth-likeelements that interlock with a cutting edge of an opposing blade, or mayhave corrugated ridges, serrations, rasp-like features, or the like. Invarious embodiments, both blades 65110 may be of equal sharpness, oralternatively one blade 65110 may be sharp and the other substantiallyflat to provide a surface against which the sharp blade 65110 may cut.Alternately or in addition, both cutting edges may be equally hard, or afirst cutting edge may be harder than a second, the latter of whichdeflects under force from the first harder edge to facilitate shearingof the target tissue.

FIGS. 185E and 185F show cross-sectional views through elongate body atlines A-A and B-B, respectively, of FIG. 185C. In some embodiments, allor a portion of elongate body 65108, such as the lower surface shown inFIG. 185E, may include a lubricious surface for facilitatingmanipulation of the tool in the surgical space and at the anatomicalsite. The lubricious lower surface also provides a barrier betweenblades 65110 and non-target tissue in the surgical space. The lowersurface may include a guide member lumen 65120 to accommodate aguidewire or other access device or rail. FIG. 185E shows distal blade65110 coupled with pull wires 65118. FIG. 185F shows proximal blade65110 b, which is not coupled with pull wires 65118 but rather fixed tobody 65108. In various alternative embodiments, proximal blade 65110 bmay be movable distally while distal blade 65110 a is static, bothblades may be moved toward one another, or a different number of bladesmay be used, such as one blade drawn toward a backstop or more than twoblades, one or more of which may be mobile. In various alternativeembodiments, guide member lumen 65120 may be accommodated on a sidesurface or more centrally within elongate body 65108. In furtheralternative embodiments, the one or more guide member lumens 65120 maycomprise one or more various cross sectional shapes, for examplesubstantially round, substantially oval, or substantially rectabular, toaccommodate alternative guide members, for example flat or rectangularguidewires, needles or rails. In still other alternative embodimentsguide member lumen 65120 may be adjustably coupled with the elongatebody 65108 to enable manipulation of the location of the elongate body65108 and therefore the tissue modifying members 65110 relative to theguiding member.

Referring now to FIGS. 185G-185I, blades 65110 are shown in their closedposition. In one embodiment, when distal blade 65110 a is drawnproximally to cut tissue, at least some of the cut tissue is captured ina hollow interior portion of elongate body 65108. Various embodimentsmay further include a cover, a cut tissue housing portion and/or thelike for collecting cut tissue and/or other tissue debris. Suchcollected tissue and debris may then be removed from the patient duringor after a tissue modification procedure. During a given tissuemodification procedure, distal blade 65110 a may be drawn proximally tocut tissue, allowed to retract distally, and drawn proximally again tofurther cut tissue as many times as desired to achieve a desired amountof tissue cutting.

Blades 65110 may be made from any suitable metal, polymer, ceramic, orcombination thereof. Suitable metals, for example, may include but arenot limited to stainless steel (303, 304, 316, 316L), nickel-titaniumalloy, tungsten carbide alloy, or cobalt-chromium alloy, for example,Elgiloy® (Elgin Specialty Metals, Elgin, Ill., USA), Conichrome®(Carpenter Technology, Reading, Pa., USA), or Phynox® (Imphy SA, Paris,France). In some embodiments, materials for the blades or for portionsor coatings of the blades may be chosen for their electricallyconductive or thermally resistive properties. Suitable polymers includebut are not limited to nylon, polyester, Dacron®, polyethylene, acetal,Delrin® (DuPont, Wilmington, Del.), polycarbonate, nylon,polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). In someembodiments, polymers may be glass-filled to add strength and stiffness.Ceramics may include but are not limited to aluminas, zirconias, andcarbides. In various embodiments, blades 65110 may be manufactured usingmetal injection molding (MIM), CNC machining, injection molding,grinding and/or the like. Pull wires 65118 be made from metal or polymerand may have circular, oval, rectangular, square or braidedcross-sections. In some embodiments, a diameter of a pull wire 65118 mayrange from about 0.001″-0.050″, and more preferably from about0.010″-0.020″.

Depending on the tissue to be treated or modified, activating blades65110 (or other tissue modifying members in alternative embodiments) maycause them to modify target tissue along an area having any of a numberof suitable lengths. In use, it may also be advantageous to limit theextent of action of blades 65110 or other tissue modifying members to adesired length of tissue, thus not allowing blades 65110 to affecttissue beyond that length. In so limiting the effect of blades, unwantedmodification of, or damage to, surrounding tissues and structures may belimited or even eliminated. In one embodiment, for example, where thetissue modification device is used to modify tissue in a spine, blades65110 may operate along a length of target tissue of no more than 10 cm,and preferably no more than 6 cm, and even more preferably no more than3 cm. Of course, in other parts of the body and to address othertissues, different tissue modification devices may be used and tissuemodifying members may have many different lengths of activity. In oneembodiment, to facilitate proper location of tissue modifying members,such as blades 65110, relative to target tissue, the tissue modifyingmembers and/or the elongate body and/or one or more additional featuresintended for just such a purpose may be composed of a material readilyidentifiable via x-ray, fluoroscopic, magnetic resonance or ultrasoundimaging techniques.

In various embodiments, a number of different techniques may be used toprevent blades 65110 (or other tissue modifying members) from extendingsignificantly beyond the target tissue. In one embodiment, for example,preventing blades 65110 from extending significantly beyond the targettissue involves holding tissue modification device 65102 as a wholepredominantly stable to prevent device 65102 from translating in adirection toward its proximal portion or toward its distal portion whileactivating blades 65110. Holding device 65102 stable is achieved byanchoring one end of the device and applying tensioning force at or nearthe other end, as described further below.

In the embodiment shown in FIGS. 185A-185I, pull wires 65118 areretracted proximally by squeezing actuator 65106 proximally. In analternative embodiment, squeezing actuator 65106 may cause both blades65110 to translate inward so that they meet approximately in the middleof window 65111. In a further embodiment, distal blade 65110 a may bereturned to it's starting position by a pulling force generated from thedistal end of device 65102, for example by using a distal actuator thatis attached to distal wires, or by pulling on the distal guide memberwhich is attached to distal blade 65110 a. In yet another alternativeembodiment, proximal blade 65110 b may be moved to cut by a pullingforce generated from the distal end of device 65102, for example byusing a distal actuator that is attached to distal wires, or by pullingon the distal guide member which is attached to proximal blade 65110 b.In yet another embodiment, squeezing actuator 65106 may cause proximalblade 65110 b to move distally while distal blade 65110 a stays fixed.In other alternative embodiments, one or more blades 65110 may moveside-to-side, one or more blades 65110 may pop, slide or bow up out ofwindow 65111 when activated, or one or more blades 65110 may expandthrough window. In another embodiment, one or more blades 65110 and/orother tissue modifying members of device 65102 may be powered devicesconfigured to cut, shave, grind, abrade and/or resect target tissue. Inother embodiments, one or more blades may be coupled with an energytransmission device, such as a radiofrequency (RF) or thermal resistivedevice, to provide energy to blade(s) 65110 for cutting, ablating,shrinking, dissecting, coagulating or heating and thus enhancing tissuemodification. In another embodiment, a rasp or file may be used inconjunction with or coupled with one or more blades. In any of theseembodiments, use of actuator 65106 and one or more moving blades 65110provides for tissue modification with relatively little overalltranslation or other movement of tissue modification device 65102. Thus,target tissue may be modified without extending blades 65110 or othertissue modification members significantly beyond an area of targettissue to be treated.

Referring now to FIGS. 4A-186C, in an alternative embodiment, a tissuemodification device 65202 may include an elongate body 65208 having aproximal portion and a distal portion 65209, a handle 65204 and actuator65206 coupled with proximal portion, and a window 65211 and tissuemodifying member 65210 disposed near distal portion 65209. As seen moreclearly in FIGS. 4B and 4C, in the embodiment shown, tissue modifyingmember 65210 comprises an RF electrode wire loop. Wire loop 65210 maycomprise any suitable RF electrode, such as those commonly used andknown in the electrosurgical arts, and may be powered by an internal orexternal RF generator, such as the RF generators provided by GyrusMedical, Inc. (Maple Grove, Minn.). Any of a number of different rangesof radio frequency may be used, according to various embodiments. Forexample, some embodiments may use RF energy in a range of between about70 hertz and about 5 megahertz. In some embodiments, the power range forRF energy may be between about 0.5 Watts and about 65200 Watts.Additionally, in various embodiments, RF current may be delivereddirectly into conductive tissue or may be delivered to a conductivemedium, such as saline or Lactate Ringers solution, which may in someembodiments be heated or vaporized or converted to plasma that in turnmodifies target tissue. Distal portion 65209 includes a tapered tip,similar to that described above, to facilitate passage of elongate body65208 into narrow anatomical sites. Handle 65204 and actuator 65206 aresimilar to those described above, although in the embodiment of FIGS.4A-186C, actuator 65206 may be used to change the diameter of the wireloop 65210. Using actuator 65206, wire loop 65210 may be caused toextend out of window 65211, expand, retract, translate and/or the like.Some embodiments may optionally include a second actuator (not shown),such as a foot switch for activating an RF generator to delivery RFcurrent to an electrode.

Elongate body 65208 may be fabricated from any suitable material andhave any of a number of configurations. In one embodiment, body 65208comprises a metal tube with a full-thickness slit (to unfold the tubeinto a flat form—not shown) or stiffening element (not shown). The splittube provides for a simple manufacturing process as well as a conductivepathway for bi-polar RF operation.

Referring to FIG. 4C, insulators 65222 may be disposed around a portionof wire loop 65210 so that only a desired portion of wire loop 65210 maytransfer RF current into the tissue for tissue modifying capability.Wire loop 65210, covered with insulators 65222 may extend proximallyinto support tubes 65218. In various alternative embodiments, anelectrode tissue modifying member (of which wire loop 65210 is but oneexample) may be bipolar or monopolar. For example, as shown in FIG. 4C,a sleeve 65224 housed toward the distal portion of window 65211 may actas a return electrode for wire loop 65210 in a bipolar device. Wire loopelectrodes 65210 may be made from various conductive metals such asstainless steel alloys, nickel titanium alloys, titanium alloys,tungsten alloys and the like. Insulators 65222 may be made from athermally and electrically stable polymer, such as polyimide,polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE),polyamide-imide, or the like, and may optionally be fiber reinforced orcontain a braid for additional stiffness and strength. In alternativeembodiments, insulators 65222 may be composed of a ceramic-basedmaterial.

In one embodiment, wire loop 65210 may be housed within elongate body65208 during delivery of tissue modification device 65202 into apatient, and then caused to extend up out of window 65211, relative tothe rest of body 65208, to remove tissue. Wire loop 65210 may also beflexible so that it may pop or bow up out of window 65211 and maydeflect when it encounters hard tissue surfaces. Wire loop 65210 mayhave any of a number of shapes, such as curved, flat, spiral or ridged.Wire loop 65210 may have a diameter similar to the width of body 65208,while in alternative embodiments it may expand when extended out ofwindow 65211 to have a smaller or larger diameter than that of body65208. Pull wires (not shown) may be retracted proximally, in a mannersimilar to that described above, in order to collapse wire loop 65210,decrease the diameter and lower the profile of the wire loop 65210,and/or pull wire loop 65210 proximally to remove tissue or be housedwithin body 65208. The low profile of the collapsed wire loop 65210,facilitates insertion and removal of tissue modification device 65202prior to and after tissue modification. As the wire loop 65210 diameteris reduced, support tubes 65218 deflect toward the center of elongatebody 65208.

In an alternative embodiment (not shown), tissue modification device65202 may include multiple RF wire loops 65210 or other RF members. Inanother embodiment, device 65202 may include one or more blades as wellas RF wire loop 65210. In such an embodiment, wire loop 65210 may beused to remove or otherwise modify soft tissues, such as ligamentumflavum, or to provide hemostasis, and blades may be used to modify hardtissues, such as bone. In other embodiments, as described further below,two separate tissue modification devices (or more than two devices) maybe used in one procedure to modify different types of tissue, enhancemodification of one type of tissue or the like.

In other alternative embodiments, tissue modification devices 65202 mayinclude tissue modifying members such as a rongeur, a curette, ascalpel, a scissors, a forceps, a probe, a rasp, a file, an abrasiveelement, one or more small planes, a rotary powered mechanical shaver, areciprocating powered mechanical shaver, a powered mechanical burr, alaser, an ultrasound crystal a cryogenic probe, a pressurized water jet,a drug dispensing element, a needle, a needle electrode, or somecombination thereof. In some embodiments, for example, it may beadvantageous to have one or more tissue modifying members that stabilizetarget tissue, such as by grasping the tissue or using tissue restraintssuch as barbs, hooks, compressive members or the like. In oneembodiment, soft tissue may be stabilized by applying a contained,low-temperature substance (for example, in the cryo-range oftemperatures) that hardens the tissue, thus facilitating resection ofthe tissue by a blade, rasp or other device. In another embodiment, oneor more stiffening substances or members may be applied to tissue, suchas bioabsorbable rods.

Referring now to FIGS. 187A-187D, one embodiment of a method formodifying tissue in a spine is demonstrated in simplified, diagrammatic,cross-sectional views of a portion of a patient's back and spine. FIG.187A shows a portion of the patient's back in cross section, with aportion of a vertebra, the spinal cord with branching nerve roots, andtarget tissue, which in this illustration is the ligamentum flavum andpossibly a portion of the facet capsule. The target tissue is typicallyimpinging directly on one or more of the group including nerve roots,neurovascular structures, dorsal root ganglia, cauda equina, orindividual nerves.

In FIG. 187B, tissue modification device 65102 has been positioned inthe patient's back to perform a tissue modification procedure. Variousmethods, devices and systems for introducing device 65102 into thepatient and advancing it to the position for modifying tissue aredescribed in further detail below. Generally, device 65102 may bepositioned via a percutaneous or open surgical procedure, according tovarious embodiments. In one embodiment, device 65102 may be insertedinto the patient through a first incision 65240, advanced into the spineand between target tissue and non-target tissue (such as spinal cord,nerve roots, nerves and/or neurovascular tissue), and further advancedso a distal portion of elongate body 65108 exits a second (or distal)incision 65242 to reside outside the patient. In positioning device65102, one or more tissue modifying members (not shown) are positionedto face the target tissue, while one or more protective portions ofelongate body 65108 face non-target tissue.

Referring to FIG. 187C, once device 65102 is positioned in a desiredlocation, anchoring force may be applied at or near the distal portionof elongate body 65108. In one embodiment, applying anchoring forceinvolves a user 65244 grasping body 65108 at or near its distal portion.In alternative embodiments, as described further below, anchoring forcemay be applied by deploying one or more anchor members disposed at ornear the distal portion of body 65108, or by grasping a guidewire orother guide member extending through at least part of body 65108. Oncethe anchoring force is applied, proximally-directed tensioning force maybe applied to device 65102, such as by pulling proximally on handle65104 (one-directional, diagonal arrows). This tensioning force, whenapplied to the substantially anchored device 65102, may help urge thetissue modifying member(s) against the target tissue (one-directional,vertical arrows near target tissue), thus enhancing contact with thetarget tissue and facilitating its modification. With the tissuemodifying member(s) contacting the target tissue, actuator 65106 may besqueezed or pulled (two-headed arrow) to cause the tissue modifyingmember(s) to modify tissue. (Alternative actuators may be activated indifferent ways in alternative embodiments.)

In various alternative embodiments, certain of the above-described stepsmay be carried out in different order. For example, in one embodimentthe distal portion of elongate body 65108 may be anchored within oroutside the patient before the tissue modifying members are positionedadjacent the target tissue. In another alternative embodiment, theproximal portion of device 65102 may be anchored, and the tensioningforce may be applied to the distal portion of device 65102. In yetanother embodiment, tensioning force may be applied to both ends of thedevice. In yet another embodiment, a second handle and actuator may becoupled with the distal end of body 65108 after it exits the patient'sback, allowing tensioning forces as well as tissue modifying actuationto occur at both the proximal and distal portions of device 65102. Byanchoring one end of device 65102 and applying tensioning force to theopposite end, contact of the tissue modifying members with the targettissue is enhanced, thus reducing or eliminating the need fortranslating or otherwise moving device 65102 as a whole and reducing theoverall profile and the resulting access pathway required to positionthe device. Reducing movement and profile of device 65102 and usingtissue modifying members confined to a relatively small area of device65102 helps facilitate target tissue modification while minimizing oreliminating damage to surrounding tissues or structures.

As mentioned above, tissue may be modified using one tissue modificationdevice or multiple devices, according to various embodiments. In oneembodiment, for example, an RF electrosurgical tissue modificationdevice may be used in the patient to remove soft tissue such asligament, and a bladed tissue modification device such as a rongeur maythen be used to remove additional soft tissue, calcified soft tissue, orhard tissue such as bone. In some embodiments, such multiple devices maybe inserted, used and removed serially, while in alternative embodimentssuch devices may be inserted into the patient at the same time to beused in combination.

Referring to FIG. 187D, using one or more tissue modification devices65102, a desired amount of target tissue may be removed from more thanone area in the spine. FIGS. 187A-187C demonstrate removal of targettissue on one side of the spine, and that method or a similar method mayalso be used to remove target tissue on an opposite side of the spine,as shown in FIG. 187D, where target tissue has been removed from bothsides. That the desired amount of tissue has been removed may beconfirmed by tactile feedback from the device or from a separate device,by testing nerve conduction through one or more previously impingednerves, by testing blood flow through one or more previously impingedblood vessels, by passing (independently or over the guide member) ameasurement probe or sound through the treated portion, through one ormore radiographic tests, through some combination thereof, or by anyother reasonable means.

Referring now to FIG. 188A, tissue modification device 65102 is shownwith one embodiment of a distal anchoring member 65250 deployed at thepatient's skin. In various embodiments, anchoring members may includebut are not limited to one or more handles, barbs, hooks, screws, togglebolts, needles, inflatable balloons, meshes, stents, wires, lassos,backstops or the like. In some embodiments, anchoring members 65250 maybe disposed at the extreme distal portion 65109 of elongate body 65108,while in other embodiments anchoring members 65250 may be located moreproximally. In the embodiment shown, anchoring members 65250 aredeployed at the patient's skin. In an alternative embodiment, anchoringmay be achieved outside the patient by deploying one or more anchoringmembers 65250 above the skin and having a user grasp the anchoringmembers 65250. In an alternative embodiment, anchoring may be achievedoutside the patient by deploying one or more anchoring members 65250above the skin and having a user grasp anchoring members 65250, aftertissue modification device 65102 has been anchored to the guide member.In another alternative embodiment, anchoring may be achieved outside thepatient by attaching anchoring member 65250 to an external device, forexample one that is mounted on the patient or on the procedure table. Ina further alternative embodiment, anchoring may be achieved outside thepatient by attaching the guide member to an external device, for exampleone that is mounted to on the patient or on the procedure table, aftertissue modification device 65102 has been anchored to the guide member.Anchoring members 65250 generally are deployable from a first,contracted configuration to facilitate delivery of device 65102, to asecond, expanded configuration to facilitate anchoring. This change inconfiguration may be achieved, for example, by using shape memory orsuper-elastic materials, by spring loading anchoring members 65250 intobody 65108 or the like. In most embodiments, anchoring members 65250 mayalso be collapsed down into the first, contracted configuration after atissue modification procedure has been performed, to facilitatewithdrawal of device 65102 from the patient. In an alternativeembodiment, anchoring members 65250 may detach from body 65108 and maybe easily removable from the patient's skin.

FIG. 188B shows tissue modification device 65102 with an alternativeembodiment of a distal anchoring member 65260. Here, distal anchoringmember 65260 includes multiple hooks or barbs extended out the distalportion 65109 of elongate body 65108 within the patient's back. In usingsuch an embodiment, it may not be necessary to pass guide member 65117through a second, distal incision on the patient, although in someembodiments guide member 65117 may extend significantly beyond distalportion 65109. Anchoring member(s) 65260, according to variousembodiments, may be deployed so as to anchor to bone, ligament, tendon,capsule, cartilage, muscle, or any other suitable tissue of the patient.They may be deployed into vertebral bone or other suitable tissueimmediately adjacent an intervertebral foramen or at a location moredistant from the intervertebral foramen. When a tissue modificationprocedure is complete, anchoring members 65260 are retracted withinelongate body for removal of device 65102 from the patient.

Referring now to FIGS. 189A-189S, a system and method for introducing atissue modification device into a spine is demonstrated. This system andmethod may be referred to as an “access system” or “access method,” inthat they provide or facilitate gaining access to a target tissue to bemodified. Of course, the embodiment shown is merely one exemplaryembodiment, and any of a number of other suitable methods, devices orsystems may be used to introduce one or more devices for modifyingtissue in spine. For example, in one alternative embodiment a spinaltissue modification procedure may be carried out through an opensurgical approach. Therefore, the following description is providedprimarily for exemplary purposes and should not be interpreted to limitthe scope of the invention as it is defined in the claims.

Referring to FIG. 189A, in one embodiment a device delivery method firstinvolves advancing an introducer cannula 65300 coupled with a stylet65302 into the patient's back. Cannula 65300 and stylet 65302 are thenpassed between adjacent vertebrae and into the ligamentum flavum or anadjacent spinal ligament, as shown further in FIG. 189B. As shown inFIG. 189C, when the distal tip of cannula is positioned as desired,stylet 65302 is removed. Referring to FIGS. 189D and 189E, a loss ofresistance syringe 65304 including a plunger 65310, barrel 65308 andfluid and/or air 65306, is coupled with the proximal portion of cannula65300. The distal portion of cannula 65300 is advanced through theligamentum flavum until it enters the central spinal canal where a lossof resistance to pressure placed on plunger 65310 is encountered, andfluid and/or air 65306 is injected into central spinal canal to confirmcorrect placement of cannula 65300 as shown in FIG. 189E. Syringe 65304is then removed, as in FIG. 189F, and a guidewire 65312 with anon-rigid, atraumatic tip is advanced through cannula 65300 into thecentral spinal canal, as in FIG. 189G. Next, cannula 65300 is removed,as in FIG. 189H, leaving behind guidewire 65312. As shown in FIGS. 189Iand 189J, an introducer sheath 65114, coupled with a dilator 65314, isthen advanced over guidewire 65312 to position a distal portion ofsheath 65114 at a desired location within the spine. Dilator 65314 andguidewire 65312 are then removed, as in FIG. 189K.

Once introducer sheath 65114 is in place, one or more curved orsteerable guide devices 65318 may be advanced through it to desiredpositions in and/or through the spine, as shown in FIGS. 189L and 189M.One or more guide members 65116, may then be advanced through the guidedevice 65318, as shown in FIGS. 189N-189P. Finally, guide device 65318may be removed, as in FIG. 189Q, and elongate body 65108 of tissuemodification device 65102 may be advanced over guide member 65116 andthrough introducer sheath 65114 to a desired position in the spine, asin FIG. 189R. As shown in FIG. 189S, elongate body 65108 may betensioned to urge tissue modifying members 65110 against target tissue,as shown with arrows at opposite ends of device 65102, while distalportion 65109 is anchored, in this case by hand 65244. In an alternativeembodiment, guide member 65116 may be tensioned to urge tissue modifyingmembers 65110 against target tissue as shown in FIG. 189R.

Once tissue modification device 65102 is in a desired position, tissueswhich may be modified in various embodiments include, but are notlimited to, ligament, tendon, tumor, cyst, cartilage, scar, “bonespurs,” inflammatory and bone tissue. In some embodiments, modifying thetarget tissue reduces impingement of the tissue on a spinal cord, abranching nerve or nerve root, a dorsal root ganglia, and/or vasculartissue in the spine. Actuator 65106 on handle 65104 is activated tomodify target tissue using tissue modification member(s) 65110, whileelongate body 65108 is held relatively stable by hand 65244 and bytension force applied to handle 65104.

In various embodiments, the system and method described immediatelyabove may include additional features or steps, may have fewer featuresor steps, may have an alternate order of implementation of steps, or mayhave different features or steps. For example, in some embodimentsplacement of device 65102 will be performed in a medial-to-lateraldirection (relative to the patient), while in alternative embodimentsdevice placement will be performed lateral-to-medial. In someembodiments, one or more components of the system described may beanchored to the patient, such as guide member 65116 or introducer sheath65114. In various embodiments, one or more guide members 65116 mayinclude one or more wires, rails or tracks and may be inserted throughguide device 65318, introducer sheath 65114 without guide device 65318,cannula 65300, an epidural needle, a lumen of an endoscope, a lumen of atissue shield or barrier device, a curved guide device 65318 placedthrough a lumen of an endoscope, or the like. In other embodiments, forexample, guide device 65318 may be placed through introducer cannula65300 and then introducer sheath 65114 may be passed over guide device65318. Tissue modification device 65102 may similarly be inserted withor without using any of these devices or components in variouscombinations. Various guidewires 65312, guide devices 65318 and/or guidemembers 65116 may be pre-shaped to have one or more curves, may besteerable, and/or may include one or more rails, tracks, grooves,lumens, slots, partial lumens, or some combination thereof.

In some embodiments, tissue modification device 65102 is insertedthrough one or more hollow devices as described above (such asintroducer sheath 65114, as shown, or cannula 65300 in an alternativeembodiment) in such a way that device 65102 expands upon extending outof a distal portion of the hollow delivery device thereby assuming awider profile for modifying a greater amount of target tissue from asingle location. In an alternative embodiment, device 65102 retains thesame overall profile during insertion and during use. In someembodiments, one or more delivery devices will remain in the patientduring use of tissue modification device 65102, while in alternativeembodiments all delivery devices are removed from the patient whentissue modification device 65102 is operating. In some embodiments,tissue modification device 65102 may be slidably coupled with one ormore delivery devices during delivery and/or during use. In oneembodiment, tissue modification device 65102 is advanced throughintroducer sheath 65114 and sheath 65114 is used as an irrigation andevacuation lumen to irrigate the area of the target tissue and evacuateremoved tissue and other debris, typically by applying a vacuum. Inalternative embodiments, tissue modification device 65102 may include anirrigation and/or evacuation lumen to irrigate an area of the targettissue and evacuate removed tissue and other debris.

Some embodiments of an access system for facilitating tissuemodification may further include one or more visualization devices (notshown). Such devices may be used to facilitate placement of the accesssystem for introducing the tissue modification device, to facilitatetissue modification itself, or any combination of these functions.Examples of visualization devices that may be used include flexible,partially flexible, or rigid fiber optic scopes, rigid rod and lensendoscopes, CCD or CMOS chips at the distal portion of rigid or flexibleprobes, LED illumination, fibers or transmission of an external lightsource for illumination or the like. Such devices may be slidablycouplable with one or more components of an access system or may beslidably or fixedly coupled with a tissue modification device. In otherembodiments, additional or alternative devices for helping position, useor assess the effect of a tissue modification device may be included.Examples of other such devices may include one or more neuralstimulation electrodes with EMG or SSEP monitoring, ultrasound imagingtransducers external or internal to the patient, a computed tomography(CT) scanner, a magnetic resonance imaging (MRI) scanner, a reflectancespectrophotometry device, and a tissue impedance monitor disposed acrossa bipolar electrode tissue modification member or disposed elsewhere ona tissue modification device or disposed on the access system.

Referring now to FIGS. 190A-190E, in an alternative embodiment, a tissuemodification device and optionally one or more introduction/accessdevices may be positioned in a patient using an open surgical technique.As shown in FIG. 190A, for example, in one embodiment an open surgicalincision is made on a patient's back, and two retractors 65402 are usedto expose a portion of the patient's vertebra. As shown in FIG. 190B, anintroducer sheath 65414 may then be inserted through the incision,between retractors 65402. As in FIG. 190C, a curved guide device 65418may then be inserted through introducer sheath 65414. Guide device 65418extends into the epidural space and through the intervertebral foramenas shown in FIG. 190D.

In some embodiments, a curved and cannulated thin, blunt probe may beplaced directly through the open incision into the epidural space of thespine, or alternatively may be placed through introducer sheath 65414.The probe tip may be advanced to or through a neural foramen. Such aprobe may be similar in shape, for example, to a Woodson elevator,Penfield 3, hockey stick probe, ball tipped probe, or the like. Inalternative embodiments, probes that may be manually bent to changetheir shapes, or probes with articulating tips, or probes with shapelock portions, and/or probes having grooves instead of cannulas may beused.

As shown in FIGS. 190D-190E, a substantially straight, flexibleguidewire 65420 with a sharp tip 65422 may then be inserted throughcurved guide device 65418 and advanced so that its distal portion withsharp tip 65422 extends outside the patient's back at a locationseparate from the open incision (FIG. 190E). Guide device 65418 may thenbe removed, as in FIG. 190F, and in subsequent steps a tissuemodification device may be inserted over guide wire 65420 and throughintroducer sheath 65414 and used to modify tissue as described in moredetail above. In an alternative embodiment, a curved, flexible cannulamay be inserted through the curved guide device, until it extendslateral to the neural foramen, after which a substantially straight,flexible guidewire with a sharp tip may then be inserted through curvedcannula and advanced so that its distal portion with sharp tip extendsoutside the patient's back.

Referring now to FIGS. 191A and 191B, another alternative open surgicalaccess method is shown. In FIG. 191A, a curved guide device 65446 isshown in place through the epidural space and intervertebral foramen,and a guidewire 65440 with a beveled distal tip 65442 is about to beadvanced through guide device 65446. As shown in FIG. 191B, in thisembodiment, guidewire 65440 is directed by guide device 65446 backthrough the open incision through which the various access devices areintroduced. In such an embodiment, then, only one incision is createdand the proximal and distal portions of one or more devices extend outof the patient's back through the same incision.

In various alternative embodiments, open surgical access may be throughexposure down to a vertebral lamina, through ligamentum flavum withoutlamina removal, through ligamentum flavum with partial or completelamina removal, through ligamentum flavum with or without lamina removalwith partial or complete medial facet joint removal, through openexposure and out through skin laterally, through open exposure and backout through the open exposure, or through a lateral open exposure thataccesses the neural foramen from the lateral side. One or morevisualization devices may be used with open surgical access proceduresas well as with percutaneous or other less invasive procedures. Inanother alternative embodiment (not shown), a tissue modification devicemay be placed in the patient directly, without any introduction devices.

Referring now to FIGS. 192A-192E, in the embodiments described above,the tissue modification devices 65102, 65202 include at least onenon-tissue-modifying (or “protective”) portion, side or surface. Thenon-tissue-modifying portion is located on tissue modification device65102, 65202 so as to be positioned adjacent non-target tissue whentissue modifying members 65110, 65210 are facing the target tissue. Thenon-tissue-modification surface of the device is configured so as to notmodify or damage tissue, and thus the non-target tissue is protectedfrom unwanted modification or damage during a tissue modificationprocedure. Alternatively, in some embodiments, a protective surface orportion of tissue modification device 65102, 65202 may actually modifynon-target tissue in a protective manner, such as by delivering aprotective drug, coating, fluid, energy or the like to the non-targettissue.

Optionally, in some embodiments, tissue modification devices or systemsmay further include one or more tissue barriers (or “shields”) forfurther protecting non-target tissues. Such barriers may be slidablycoupled with, fixedly coupled with, or separate from the tissuemodification devices with which they are used. In various embodiments, abarrier may be delivered between target and non-target tissues beforedelivering the tissue modification device, may be delivered along withthe tissue modification device, or may be delivered after delivery ofthe tissue modification device but before the device is activated orotherwise used to modify target tissue. For example, a barrier (or“shield”) may be coupled to the distal and proximal ends of a tissuemodification device, specifically, it may be coupled to the distal andproximal ends of the tissue modification region (or distal flexibleregion) of a tissue modification device. For example, the device mayslide over the distal tip of the device and then clip onto a proximalportion of the device. The barrier may be made from a flexible and/orlubricious material, such as Teflon, for example. In this example, thebarrier may be delivered along with the tissue modification device. Thebarrier may be configured to reciprocate with the tissue modificationdevice or alternatively, the barrier may be configured to remainstationary as the tissue modification device reciprocates over or abovethe barrier. In this variation, the barrier may be configured to coupleto the tissue modification device such that the tissue modificationdevice (or guidewire) may pull the barrier only in one direction. Forexample, the tissue modification device (or guidewire) may pull thebarrier in a distal direction toward the desired location within thespine (e.g. adjacent to non-target tissue) but will not pull the barrierproximally and will allow the barrier to remain in place will the deviceis pulled proximally.

In some embodiments, a first barrier may be removed from the device anda new or replacement barrier may be coupled to the device during use ofthe tissue modification device. For example, a user may remove tissuefrom a first portion of a spine while a first barrier is in place, thenthat first barrier may be removed and a second barrier may be coupled tothe device prior to removing tissue from a second portion of a spine.Alternatively, in some alternative embodiments, rather than, or inaddition to, coupling a barrier to a tissue modification device, alubricant, such as a sterile lubricant, may be applied to a portion ofthe tissue modification device, specifically for example, the portionthat may come into contact with non-target tissues. Generally, such abarrier or lubricant may be interposed between the non-target tissue andone or more tissue modification devices to prevent unwanted damage ofthe non-target tissue.

FIG. 192A shows a distal portion of an introducer device 65514 throughwhich a barrier may be introduced. FIGS. 192B and 192C show oneembodiment of a barrier 65500 partially deployed and in cross-section,respectively. Typically, barrier 65500 will have a first, small-profileconfiguration for delivery to an area near non-target tissue and asecond, expanded configuration for protecting the non target tissue. Invarious embodiments, barrier 65500 may have any of a number of sizes andshapes. For example, barrier 65500 is shown in FIG. 192B with a taperedend. In an alternative embodiment, barrier 65500 may instead have asquared-off end, a more rounded end, or the like. In fact, many of theembodiments shown in subsequent figures have squared-off ends. Many, ifnot all, embodiments described herein may have either a tapered end, asquared-off end, a rounded end, or any other suitable shape inalternative embodiments.

In various embodiments, some of which are described more fully below,barrier 65500 may be configured as one piece of super-elastic orshape-memory material, as a scaffold with material draped between thescaffolding, as a series of expandable wires or tubes, as a semicircularstent-like device, as one or more expandable balloons or bladders, as afan or spring-loaded device, or as any of a number of different devicesconfigured to expand upon release from delivery device 65514 to protecttissue. As shown in FIGS. 192B and 192C, barrier 65500 may comprise asheet of material disposed with a first end 65502 a abutting a secondend 65502 b within introducer device 65514 and unfurling upon delivery.

In an alternative embodiment, as shown in FIGS. 192D and 192E, oppositeends 65522 a and 65522 b of a barrier 65520 may overlap in introducerdevice 65514. Generally, barrier 65500, 65520 may be introduced viaintroducer device 65514 in one embodiment or, alternatively, may beintroduced via any of the various means for introducing the tissuemodification device, such as those described in conjunction with FIGS.189A-189S, 190A-190F and 191A-191B. In some embodiments, barrier 65500,65520 may be fixedly coupled with or an extension of a tissuemodification device. Barrier 65500, 65520 may also include one or morelumens, rails, passages or the like for passing a guidewire or otherguide member, for introducing, removing, steering, repositioning, orexchanging any of a variety of tissue modification, drug delivery, ordiagnostic devices, for passing a visualization device, for passing adevice designed for neural localization, for providing irrigation fluidand/or suction at the tissue modification site, and/or the like. In someembodiments, barrier 65500, 65520 is advanced over multiple guidewiresand the guidewires remain in place during a tissue modificationprocedure to enhance the stability and/or maintain positioning ofbarrier 65500, 65520.

Introducer device 65514, which is alternatively referred to as adelivery device 65601 in FIG. 193 et seq., may comprise any suitablecatheter, introducer, sheath or other device for delivering one or morebarrier devices into a patient. In various alternative embodiments,barrier devices may be delivered into a patient either through adelivery device, over one or more guide members, or both. Various guidemember embodiments will be described in greater detail below. In variousembodiments, introducer device 65514 or delivery device 65601 may haveany suitable dimensions, profile or configuration. For example, invarious embodiments, introducer device 65514 may have a circularcross-sectional shape, an oval cross-sectional shape, or a shape thatvaries between circular and oval along the length of device 65514. Insome embodiments, an outer diameter of introducer device 65514 ordelivery device 65601 may range from about 0.025″ to about 1.0″, with awall thickness range of about 0.001″ to about 0.125″. Optionally,introducer device 65514 or delivery device 65601 may taper along itslength. Introducer device 65514 or delivery device 65601 may rigid,partially flexible or flexible along its entire length and may be madefrom any suitable material, such as but not limited to: a metal, such asstainless steel (303, 304, 316, 316L), nickel-titanium alloy,cobalt-chromium, or nickel-cobalt; a polymer, such as nylon, silicone,polyetheretherketone (PEEK), polyetherketoneketone (PEKK),polytetrafluoroethylene (PTFE), polyurethane (Tecothane), Pebax (co,USA), polycarbonate, Delrin (co, USA), high-density polyethylene (HDPE),low-density polyethylene (LDPE), HMWPE, and UHMWPE; or a combination ofmetals and polymers. Introducer device 65514 or delivery device 65601may be manufactured by methods known in the art, such as CNC machining,extruding, casting, injection molding, welding, RF shaping,electrochemical fabrication (EFAB), LIGA (lithographic, galvanoformingand abforming), electrical discharge machining (EDM) laser machining,silicon micromachining, weaving, braiding or non-woven fabricationtechniques (e.g., spunbound, meltblown, and the like). In someembodiments, introducer device 65514 or delivery device 65601 may bewoven from polymer or metal into a tube-like structure for flexibilityand conformability. Such embodiments may optionally be fiber-reinforcedfor added strength to allow for a thinner wall thickness.

Referring now to FIGS. 193A and 193B, an alternative embodiment of abarrier 65602 comprising a woven, braided or non-woven material with alattice structure 65604 is shown. FIG. 193A shows barrier 65602 beingdeployed from delivery device 65601, and FIG. 193B shows barrier 65602in its completely deployed (expanded, free) configuration. In variousembodiments, barrier 65602 may have any of a number of suitabledimensions. For example, in some embodiments, barrier 65602 may have awidth ranging from about 0.100″ to about 3.000″, a length ranging fromabout 0.100″ to about 72″, and a thickness ranging from about 0.001″ toabout 0.250″. In some embodiments, as described in connection with FIGS.192B and 192D above, barrier 65602 may have a narrowed or tapered distalend. Barrier 65602 may be manufactured by methods known in the art, suchas in a single-layer flat-form or a dual-layer tubular-form that ispressed flat. Material used to fabricate barrier 65602, in variousembodiments, may be composed of a weave of metallic wire, monofilamentor braided. The metallic wire may be made from any suitable material,such as stainless steel (303, 304, 316, 316L), nickel-titanium alloy,cobalt-chromium alloy, Elgiloy® (Elgin Specialty Metals, Elgin, Ill.,USA), Conichrome® (Carpenter Technology, Reading, Pa., USA), Phynox®(Imphy SA, Paris, France) or the like. A woven material may be composedof a weave of polymer strands, monofilament or braided material. Polymerstrands in a woven, braided or non-woven material construction may bemade from nylon, polyester, Dacron®, polyethylene, Kevlar® (DuPont),acetal, Delrin® (DuPont), polycarbonate, nylon, silicone,polyetheretherketone (PEEK), polyetherketoneketone (PEKK),polytetrafluoroethylene (PTFE), polyurethane, UHMWPE, or the like. Insome embodiments, barrier 65602 may self-expand after being releasedfrom a constrained configuration in delivery device 65601. In someembodiments, such self-expansion may be achieved by forming barrier65602 from a shape-memory or super-elastic material.

Referring to FIGS. 193C and 193D, in an alternative embodiment, abarrier 65612 may include multiple slits 65615 extending from oppositeedges 65613 a, 65613 b toward the longitudinal center of barrier 65612to form multiple tabs 65616. Slits 65615 may enhance flexibility ofbarrier 65612 by allowing tabs 65616 to flex independently. Tabs 65616may then return to their flat-form state individually as delivery device65601 is pulled proximally, as shown in FIG. 2D. Tabs 65616 may alsoconform individually to surrounding tissue, thereby helping protectnon-target tissue, in some embodiments. Barrier 65612 may be made of anysuitable material, such as but not limited to those described above, andslits 65615 may be formed by any suitable method, such as die cutting,milling machining, laser cutting, EDM machining, injection molded,etching, water-jet cutting, and blade cutting. In an alternativeembodiment, barrier 65612 may be made by assembling multiple tabs 65616to a central member by welding, soldering, brazing, or laser welding,for example.

FIGS. 193E and 193F illustrate another alternative embodiment of abarrier 65622 having slits 65627 disposed more centrally and notextending to the lateral edges 65623 a, 65623 b.

In another alternative embodiment, shown in FIGS. 193G and 193H, abarrier 65632 comprises a central support member 65639 and multiplelateral ribs 65638 that form a skeleton-like framework. In variousembodiments, central member 65639 and ribs 65638 may either comprise thesame material or different materials, and any suitable materials may beused, such as but not limited to the materials listed above. In someembodiments, ribs 65638 may retain a curvilinear shape after deploymentthat is heat-set in nickel-titanium or mechanically formed, as shown inFIG. 193G.

Referring to FIGS. 193I and 193J, in another alternative embodiment, abarrier 65642 may comprise a flat-form sheet made from polymer, porouspolymer, woven or non-woven fabric, metal, porous metal, foam, hydrogel,a double-layer polymer “bag” to create an inflatable bladder, or thelike.

Referring to FIGS. 193K and 193L, in another alternative embodiment, abarrier 65652 may comprise a central support member 65650 and ribs 65659that straighten completely or nearly completely upon deployment.Optionally, barrier 65652 may also include a flex-point 65651 at whichbarrier 65652 may articulate.

With reference now to FIGS. 194A-194C, in one embodiment a barrier 65662may include ridges 65672 disposed along opposite lateral edges 65663 a,65663 b. Ridges 65672 may be configured to engage with and slide throughrecessed channels (or grooves) in a guide member 65673, as shown in FIG.194C. In this embodiment, guide member 65672 may be used for advancingbarrier 65662 into a patient, and it may not be necessary to use asheath or catheter-type delivery device. Optionally, guide member 65673may include one or more reinforcing members (not shown) to give itstrength and stiffness. In some embodiments, such reinforcing membersmay have a pre-set shape (such as an arc) along their length, which mayhelp guide barrier 65662 into a desired location. Examples ofreinforcing elements include, but are not limited to, a wire, ahypotube, a monofilament, braided polymer, and the like.

Referring to FIGS. 195A and 195B, in another alternative embodiment, abarrier 65682 may suitably include a groove 65685 that may be split by aseparating member 65684 to deploy barrier 65682. Separating member 65684may be coupled with an inner cannula 65686 (or rod), which may beretracted (arrow) to cause separating member 65684 to split barrier65682 along groove 65685. In some embodiments, as shown in FIG. 195B,barrier 65682 may include a tapered distal end 65687 to facilitateadvancement of barrier 65682 into a patient and/or through a deliverydevice. Separating member 65684 may have any suitable shape andconfiguration and may comprise, in various embodiments, a post, a blade,a wedge, or the like.

FIGS. 196A-196C show another embodiment of a barrier 65692, including azipper-like seam comprising multiple interdigitating teeth 65698, whichjoin together the opposite edges 65693 a, 65693 b of barrier 65692. Asshown in FIG. 196B, teeth 65698 include a port 65699 approximatelyaligned with the longitudinal axis of barrier 65692, which accommodatesa pull rod 65700. When pull rod 65700 is retracted proximally, as inFIG. 196A, teeth 65698 are freed from one another and the zipper-likeseam unzips to deploy barrier 65692. Teeth 65698 may have any of anumber of shapes, such as but not limited to triangular (as shown),rectangular, curvilinear, or any other interdigitating (nesting,interlocking) geometry. In various embodiments, pull rod 65700 may bemade of metal or polymer, monofilament or braided.

Referring now to FIGS. 197A and 197B, in one alternative embodiment, abarrier device 65702 may suitably include an expandable or shapechanging portion 65703, a tapered distal portion 65707, an elongateproximal portion 65705, and a guidewire lumen 65709 to allow passage ofbarrier device 65702 over a guidewire 65701. In some embodiments,barrier device 65702 may be passed over guidewire 65701 and through adelivery device 65601, as shown in FIG. 197B. In various embodiments,shape changing portion 65703, distal portion 65707 and proximal portion65705 may have any desired lengths, widths and thicknesses. For example,in one embodiment barrier device 65702 may have an overall length suchthat proximal portion 65705 may extend outside a patient through a firstentry point, and distal portion 65707 may extend outside a patientthrough a second entry point, while shape changing portion 65703 residesbetween target and non-target tissue, such as tissue in a spine or otherlocation in the body. In such an embodiment, tensioning and/or anchoringforces may be applied to both proximal portion 65705 and distal portion65707 so that shape changing portion 65703 may urge part of a tissuemodification device against target tissue. In alternative embodiments,only proximal portion 65705 or only distal portion 65707 may havesufficient length to extend outside a patient while shape changingportion 65703 is in position between target and non-target tissues. Insome embodiments, barrier device 65702 may be fabricated from a singlepiece of material.

Turning now to FIGS. 198A-198G, in another embodiment, a barrier device65712 may include a shape changing portion 65713, a distal portion65718, and a proximal portion 65715. Shape changing portion 65713 mayinclude frame comprising a central support member 65716 and lateralsupport members 65714, with material disposed over, around or betweenthem. Central support member 65716 may help support shape changingportion 65713 and may also act to expand the frame. In some embodiments,central support member 65716 may have a tubular configuration toaccommodate a guidewire. Alternatively, lateral support members 65714may be pre-shaped or biased to expand automatically when deployed from adelivery device 65601. Lateral members 65714, for example, may comprisehypotubes, flat material, solid rods, or braided wires, in variousembodiments. Distal portion 65718 may be formed and attached to centralsupport member 65716 and lateral support members 65714 by methods knowin the art, for example, resistance welding, over-molding, brazing,laser-welding, or the like. In various embodiments, barrier device 65712may be housed in delivery device 65601 in any of a number ofconfigurations, such as but not limited to those shown in FIGS.198B-198D. In one embodiment, barrier device 65712 may be stored indelivery device 65601 in a flat configuration, as shown in thecross-sectional view of FIG. 198B, and may be stretched when deployedfrom delivery device 65601, as depicted in FIG. 198E. Alternatively,barrier device 65712 may be a stored in delivery device 65601 in afolded (ruffled) configuration, as shown in the cross sectional view ofFIG. 198C, and may be unfolded when deployed from delivery device 65601,as depicted in FIG. 198F. Alternatively, barrier device 65712 may be astored in delivery device 65601 in a rolled (overlapped) configuration,as shown in the cross sectional view of FIG. 198D, and may be unrolledwhen deployed from delivery device 65601, as depicted in FIG. 198G. Asshown, in various embodiments, shape changing portion 65713 of barrierdevice 65712 may assume any of a number of suitable deployedconfigurations.

Referring to FIG. 199, in another alternative embodiment, a barrierdevice 65722 may have a fan-like or corrugated configuration, includingmultiple bends 65724, folds, hinges, creases or the like. In variousembodiments, barrier device 65722 may open automatically upon extendingout of a delivery device 65601 or, alternatively, may be opened with theuse of one or more actuators. In various embodiments, bends 65724 may beformed by bending and yielding the material to take a permanent set orby bending elastically to the point where the material does not take aset and returns to the original state when unconstrained. Bends 65724may also be formed as “live” hinges. A “live hinge” is a groove (edge,line, trough) of reduced thickness used to create a more flexible regionin a body of material, which may be produced using various techniquesknown in the art. The stiffness and thickness of barrier device 65722may be adjusted in various embodiments to provide desired self-expandingproperties. In various alternative embodiments, barrier device 65722 mayhave a narrowed, tapered or rounded distal end instead of thesquared-off end shown in FIG. 199.

In an alternative embodiment, as shown in FIG. 200, a barrier device65732 may include multiple, attached, compliant tubes 65734, which maybe compressed to fit within a delivery device 65601, and which expandwhen released from delivery device 65601. In one embodiment, tubes 65734may be made of polymer and may be bonded, fastened, RF welded, attachedtogether with adhesive, or the like. In an alternative embodiment,barrier device 65732 may be extruded as a single piece of material. Inalternative embodiments, the distal ends of tubes 65734 may be sealedand pressure applied to the proximal ends may be used to expand barrierdevice 65732 when it exits deliver device 65601. In alternativeembodiments, either of barrier device 65722 or 65732 may have a distalportion at which the device tapers to a more low-profile configuration,as in the barrier devices of FIGS. 197 and 198.

Referring to FIG. 201, in another embodiment, a barrier device 65742 mayinclude a straight central support member 65746 and straight lateralsupport members 65744, with material covering or stretched between themembers 65746, 65744. In some embodiments, as shown in FIGS. 202A and202B, a barrier device 65752 may include a central support member 65756,lateral support members 65754, and a push rod 65757 ending in a diverter65758. Diverter 65758 may act to redirect the applied force from theproximal end of push rod 65757 to apply an outward force on lateralsupport members 65754, thereby expanding barrier device 65742. Centralmember 65756 may include a lumen or dual-lumen to allow passage of pushrod 65757 therethrough. Diverter 65758 may have any suitable angle invarious embodiments, such as between about 45 degrees and about 135degrees, or more preferably between about 75 degrees and about 115degrees.

In yet another embodiment, and with reference now to FIG. 203, a barrierdevice 65762 may include a central support member 65766 and lateralsupport members 65764 having bends 65768 to increase barrier device's65762 surface area. In various embodiments, lateral support members65764 may have any number of bends, arcs or geometries to enhancefunctionality of barrier device 65762. Bends 65768 may be included inthe design of barrier device 65762 as provided from the manufacturer ormay be modified by a surgeon or other user to customize barrier device65762 during a procedure.

Referring to FIGS. 204A and 204B, in another embodiment, two halves of abarrier device 65772 may be rolled from lateral support members 65774toward a central support member 65776, to assume a low-profileconfiguration for delivery through a delivery device 65601. When barrierdevice 65772 is exposed out the distal end of delivery device 65601,each lateral support member 65774 may be turned about an axis 65778 tounroll barrier device 65772.

In another embodiment, as shown in FIG. 205, a barrier device 65782 mayinclude a scaffold and material draped over or between elements of thescaffold. For example, barrier device 65782 may include multiple centralsupport members 65786 and lateral support members 65784, and anarticulated mechanism 65788 including multiple linking members 65790 andhinges 65787. Articulated mechanism 65788 may be expanded and collapsed,for example, via an actuator 65785, which may comprise a pull wire, pushrod or the like in various embodiments. In one embodiment, articulatedmechanism 65788 may apply an outward force when articulator 65785 isadvanced in a distal direction. Alternatively, articulated mechanism65788 may apply an outward force when articulator 65785 is retracted ina proximal direction.

With reference now to FIGS. 206A-206E, two additional alternativeembodiments of a barrier device 65802, which may be advanced through adelivery device 65601 are shown. In some embodiments, delivery device65601 completely houses barrier device 65802 before deployment, as inFIG. 206A. In the embodiment shown in FIGS. 206B and 206C, barrierdevice 65802 includes a “4-bar linkage” including two longitudinalsupport members 65804 and two transverse support members 65806, allcoupled together via multiple hinges 65807, flexure points, or pivotpoints. As shown in FIG. 206B, one longitudinal support member 65804 maybe retracted proximally (arrow) to collapse barrier device 65802. Asshown in FIG. 206C, one longitudinal support member 65804 may also beadvanced distally to expand barrier device 65802. In some embodiments,support members 65804, 65806 may be rigid, while in alternativeembodiments some or all may be flexible. In an alternative embodiment(not shown), transverse support member 65806 most proximal to deliverydevice 65601 may be eliminated to create a “3-bar linkage” mechanism. Inyet another embodiment, as shown in FIGS. 206D and 206E, additionaltransverse support members 65806 may be added to barrier device 65802 toprovide additional support.

In another alternative embodiment, and referring now to FIGS. 207A and207B, to provide additional support, a barrier device 65812 may includeeven more transverse support members 65819, joined to a central supportmembers 65816 and lateral support members 65814 by a hinges 65818 (orpivots, flexure points or the like). In some embodiments, pullingcentral support member 65816 may cause barrier member 65812 to expand(FIG. 207B), and pushing central support member 65816 distally may causebarrier device 65812 to collapse (FIG. 207A). In an alternativeembodiment, pulling central support member 65816 may cause barrierdevice 65812 to collapse, and pushing central support member 65816distally may cause barrier device 65812 to expand. In alternativeembodiments, to create a curvature in the plane of barrier device 65812,the transverse support members 65819 may have arc-like shapes. Invarious embodiments, a flexible material or membrane may cover, bestretched between, or otherwise be coupled with support members 65814,65816, 65819.

Referring to FIGS. 208A-208E, in another embodiment, a barrier device65822 may include lateral support members 65824 coupled withflex-linkages 65826. One version of a flex-linkage 65826 may be formedfrom wire, as shown in FIG. 208B, with a central loop 65828 to providestrain relief. Flex-linkages 65826 may deform resiliently when lateralsupport members 65824 impart an inward force, either during manipulationin a surgical field or as a delivery device 65601 is advanced distally,as shown in the various configurations of barrier device 65822 depictedin FIGS. 208C-208E.

FIGS. 209A and 209B illustrate another alternative embodiment of abarrier device 65832, in which device 65832 comprises a tubular, wovenmesh. Barrier device 65832 may assume an elongate, low-profileconfiguration, as in FIG. 209A, to facilitate its delivery to atreatment area, and may also be compressed from one or both ends toassume a widened/expanded configuration for protecting tissue, as inFIG. 209B. In another embodiment, as in FIGS. 210A and 210B, a barrierdevice may comprise a flat woven mesh.

Another alternative embodiment of a barrier device 65852 is depicted inFIGS. 211A and 211B. Here, a first pull wire 65854 and a second pullwire 65855, extending from opposite ends of a shape changing portion ofbarrier device 65852, may be pulled to cause the shape changing portionto expand or widen (FIG. 211B). In some embodiments, when pull wires65854, 65855 are released, the shape changing portion may resume itsoriginal, narrower configuration (FIG. 211A).

Referring now to FIGS. 212A-212F, in another embodiment, a barrierdevice 65862 may be housed in a housing 65864 comprising two halves65866, 65868, and a lumen for allowing passage of a guidewire 65869.When halves 65866, 65868 are pulled apart, as in FIG. 212B, barrierdevice 65862 is free to expand. FIGS. 212C-212F illustrate a method fordeploying barrier device 65862 between target and non-target tissue,such as bone and soft tissue. In FIGS. 212C and 212D, housing 65864 ispositioned between the bone and soft tissue. In FIGS. 212E and 212F,halves 65866, 65868 are pulled apart to expose barrier device 65862 andthus allow it to expand. In various embodiments, housing 65864 may havean atraumatic (or blunt) end or ends and may be advanced to a positionbetween tissues using any of a number of suitable methods. For example,housing 65864 may be advanced by itself between the tissues, may beadvanced over one or more guidewires or other guide members, may beadvanced through a delivery sheath or other delivery device, or somecombination thereof.

In another embodiment, as shown in FIGS. 213A-213C, a barrier device65872 may include a woven wire structure including lateral straightwires 65874 coupled with crossing wires 65877, 65878 via multiple loops65876. In one embodiment, lateral wires 65874 slide freely through loops65876, to allow barrier device 65872 to collapse and expand. Wires65876, 65877, 65878 may be coupled with end caps 65880, 65881 at eitherend of barrier member 65872. Some embodiments may also include pull tabs65879, 65882 at either end of barrier member 65872. As shown in FIG.213C, when pull tabs 65879, 65882 are pulled, barrier device 65872 mayshorten and expand to a wider configuration. As shown in FIGS. 213A and213C, when pull tabs 65879, 65882 are pulled, an angle between crosswires 65877, 65878 decreases. In an alternative embodiment, pulling pulltabs 65879, 65882 may cause barrier device 65872 to collapse. In someembodiments, wires 65874, 65877, 65878 themselves may perform theprotective function of barrier member 65872, while in alternativeembodiments a material or membrane may be coupled with wires 65874,65877, 65878.

Referring now to FIGS. 214A-214C, in another alternative embodiment, abarrier device 65892 may include a piece of hydrogel material, whichexpands and/or unrolls from a collapsed/rolled configuration (FIG. 214A)to an expanded/unrolled configuration (FIG. 214C) when exposed to one ormore fluids, such as saline, water, blood or the like. In oneembodiment, hydrogel may be injected directly into an area betweentarget and non-target tissues to form barrier device 65892, and device65892 may be left in the patient's body to dissolve after a tissuemodification procedure is complete. In other alternative embodiments,barrier device 65892 may comprise one or more alternative self-expandingmaterials or materials that expand upon exposure to fluid.

In yet another embodiment, as shown in FIGS. 215A-215C, a barrier device65902 may have a cup-like or scoop-like shape formed by multiple supportmembers 65904 coupled with a material or membrane. This embodiment ofbarrier device 65902 may function and be fabricated in a similar mannerto a number of the embodiments described above. The cup-like shape mayenhance the ability of barrier device 65902 to protect multiple surfacesof non-target tissue.

FIGS. 216A-216C show another alternative embodiment, in which a barrierdevice 65912 has a stent-like configuration including multipleexpandable/collapsible slats 65917 disposed between tubular portions65914, 65918 at either end. In one embodiment, a pull wire 65916 may bepulled to cause slats 65917 to flex, thus expanding barrier device 65912(FIGS. 216B and 216C). In various embodiments, pulling pull wire 65916may cause all or only a subset of slats 65917 to expand. As shown in theside view of FIG. 216C, for example, if a subset of slats 65917 isexpanded, barrier device 65912 may form a cup-like shape that may beused to forcibly displace tissue or create additional space in asurgical field. In alternative embodiments, slats 65917 may self-expandor may expand via some other mechanism, such as a push rod or otheractuator. In other alternative embodiments, any number, size or shape ofslats may be incorporated into barrier member 65912. In someembodiments, barrier device 65912 may be delivered to a desired locationin a patient without use of a sheath or catheter delivery device butinstead simply over a guidewire. In other embodiments, such as whenslats 65917 are self-expanding, barrier member 65912 may be deliveredthrough a sheath or catheter.

With reference now to FIGS. 217-217H, a number of various embodiments ofshaped-wire barrier devices 65922, 65932, 65942, 65952 are shown. Asseen in FIG. 217, in one embodiment a delivery device 65601 maycompletely or almost completely house a barrier member. A cap member65926 may be exposed out of the distal end of delivery device 65601, anda barrier member may be pushed distally out of delivery device to exposea shape changing portion that self-expands (FIGS. 217A, 217C, 217E and217G). FIGS. 217A and 217B are perspective and end-on views of oneembodiment of a barrier device 65922 having a flat, spiral shapechanging portion that resides predominantly in one plane 65927 and aproximal portion 65924, which may be used to advance barrier device65922 through delivery device 65601. In alternative embodiments, barrierdevice 65922 may be preformed to have a certain shape when released fromconstraint or, alternatively, device 65922 may be deflected by adeflection member 65928 to assume a shape.

FIGS. 217C-217H are perspective and end-on views of various embodimentsof shaped-wire barrier devices 65932, 65942, 65952, each including ashape changing distal portion and a proximal portion 65934, 65944, 65954for advancing the barrier device. As seen in the figures, a shaped-wirebarrier device may have a helical shape (932, FIGS. 217C and 217D), azig-zag shape (942, FIGS. 217E and 217F), or an overlapping loop shape(952, FIGS. 217G and 217H). In alternative embodiments, shaped-wirebarrier devices may have any of a number of other suitable shapes, sizesor configurations.

In still another embodiment, and with reference now to FIGS. 218A and218B, a barrier device 65962 may comprise one or more expandablebladders 65962, balloons or the like, which may be expanded byintroduction of a gas, liquid or solid expansion medium via an fillingtube 65966. In various embodiments, for example, bladder 65962 may befilled and caused to expand (FIG. 218B) using an expansion medium suchas air, carbon dioxide (CO2), nitrogen (N2), water, saline, siliconeoil, hydrogel, powder, particulate, beads, or any of a number of othermedia. As bladder 65962 is filled via filling tube 65966, bladder 65962may both expand and become firmer.

Referring to FIGS. 219A-219E, in one embodiment, an expandable bladderbarrier device 65972 may include multiple solid particles 65973 disposedwithin device 65972, an inflation tube 65974 and a suction tube 65975.Air, other gases, saline, water or the like may be introduced intobladder barrier device 65972 through inflation tube 65974, thus causingseparation of particles 65973 and making device 65972 flexible andadjustable, as in FIGS. 219A-219C. Device 65972 may be adjusted into adesired shape when flexible, and then air, fluid or the like may beremoved from device 65972 using suction tube 65975, thus bringingparticles 65973 closer together and making device 65972 more solid/firm,as in FIGS. 219D and 219E. Any suitable particles 65973 may be used, invarious embodiments, and particles 65973 may have any of a number ofsuitable shapes, such as those shown in FIG. 219F. For example, smoothparticles 65976, rough particles 65977, particles with parallel grooves65978 or particles with crossing grooves 65979 may be used in variousembodiments. Of course, other particles may be used in other alternativeembodiments, and particles may be made of any suitable material, such asmetal, polymer, ceramic, bioabsorbable material, or the like. The sizeof the particles 65973 may vary from that of a fine powder to a largerparticulate with a diameter of about 0.250″, for example.

With reference to FIGS. 220A-220C, in another embodiment, a barrierdevice 65982 may include a bladder 65983 and a fill tube 65984controlled by a valve (not shown). Bladder 65983 may contain a compliantfoam material 65986 (FIG. 220C, cross-sectional view), which may allowbarrier device 65982 to unfurl and/or expand by opening the valve offill tube 65984 to allow air, fluid or the like to enter bladder 65983,as shown in FIG. 220A. Alternatively or additionally, air, fluid or thelike may be forced into bladder 65983 through fill tube 65984 bypositive pressure. Air, fluid or the like may be removed from bladder65983 by applying vacuum via fill tube 65984, thus causing barriermember 65982 to collapse/deflate to facilitate storage, rolling,delivery through a delivery device and/or the like. In some embodiments,foam material 65986 may be bonded to the inside of bladder 65983, suchthat the shape of expanded barrier device 65982 may be constrained in adesired configuration.

Referring to FIGS. 221A-221C, in another embodiment, a barrier device65992 having two lateral support members 65994 may be delivered using adual-lumen delivery device 65991. The two lumens of delivery device65991 may be formed by two tubes 65996, which may be joined along partof their lengths, thus forming a groove 65998 (FIG. 213A andcross-section 213B), and may be divided along a different portion oftheir lengths (FIG. 213A and cross-section 213C). In variousembodiments, tubes 65996 may have any suitable sizes, shapes orconfigurations and may be made of any suitable material. Optionally, inone embodiment, tubes 65996 may coalesce into a common lumen at atapered distal tip 65999. Barrier device 65992 may be shaped like awedge and have lateral support members 65994 sized and shaped to slidethrough lumens formed by tubes 65996.

In two additional alternative embodiments, as shown in FIGS. 222A-222D,a barrier device 651002 may include a central wedge 651007 and multiplelateral wedges 651008, with each wedge 651007, 651008 comprising lateralsupport members 651004 configured to slide through channels 651006 ofadjacent wedges 651007, 651008. FIGS. 222A and 222C are perspective andend-on views, respectively, of an embodiment of barrier device 651002 inwhich wedges 651007, 651008 slide in the same plane. FIGS. 222B and 222Dare perspective and end-on views, respectively, of an embodiment ofbarrier device 651002 in which wedges 651007, 651008 slide in differentplanes. A control rod 651003 extends proximally from each lateralsupport member 651004, to allow for positional adjustment wedges 651007,651008. In various embodiments, wedges 651007, 651008 may have anysuitable number, size or shape. In the embodiment shown in FIGS. 222Band 222D, wedges 651007, 651008 are slidably coupled together viacorresponding rolled edges 651009.

In another alternative embodiment, as shown in FIGS. 223A-223C, abarrier device 651012 may suitably include a central support member651018, lateral support members 651014, and multiple protrusions 651016coupled with support members 651018, 651014. When protrusions 651016,which are shown as spherical but may have any suitable shape and size invarious alternative embodiments, are out of alignment with one another(i.e., not contacting adjacent protrusions 651016), as in FIG. 223A,barrier device 651012 assumes a narrower configuration. When centralsupport member 651018 is retracted proximally, as in FIG. 223B (arrow),protrusions 651016 align (or “nest”) and thus contact one another toexpand/widen barrier device 651012. In alternative embodiments,protrusions 651016 may be brought into alignment/contact by advancingcentral member 651018, advancing or retracting lateral members 651014 orby any other method. In an alternative embodiment, protrusions 651019may comprise a boss and a triangular cross-section, as shown in FIG.223C, which may facilitate the un-nesting process.

Referring to FIG. 224, in yet another embodiment, a barrier device651040 may include a sleeve of material 651042 covering a shaped wire651044. Wire 651044 may be adjustable from a straight configuration fordelivery to a shaped configuration (as shown) for protecting tissue. Insome embodiments, wire 651044 may be pushed and/or pulled from oppositeends (double-headed arrows) to change its shape, while in otherembodiments wire 651044 may automatically change its shape upon releasefrom constraint inside a delivery catheter or other delivery device.

FIGS. 225A and 225B illustrate how, in one embodiment, a barrier device651020 extending through a delivery device 65601 may help protect tissueduring a tissue modification procedure involving use of a tissuemodification device 651024. In various embodiments, tissue modificationdevice 651024 may include, but is not limited to, a rongeur, a curette,a scalpel, one or more cutting blades, a scissors, a forceps, a probe, arasp, a file, an abrasive element, one or more small planes, anelectrosurgical device, a bipolar electrode, a unipolar electrode, athermal electrode a rotary powered mechanical shaver, a reciprocatingpowered mechanical shaver, a powered mechanical burr, a laser, anultrasound crystal, a cryogenic probe, a pressurized water jet, or anycombination of such devices. Tissue modification device 651024 may beadvanced and retracted (double-headed arrows) freely on one side ofbarrier device 651020 and may be used to modify tissue, while barrierdevice 651020 protects non-target tissue from sustaining unwanteddamage. In some embodiments, barrier device 651020 may also be used tohelp guide tissue modification device 651024 to and/or from a positionfor performing a tissue modification procedure. Such guidance may beachieved by a shape, surface characteristic and/or one or more guidefeatures of barrier device 651020, according to various embodiments.

Turning to FIGS. 226A and 226B, in another embodiment, a barrier device651030 may include an open, shape-changing portion 651030, closed,elongate extensions 651034 extending from either end of shape-changingportion 651030, and at least one guide feature 651035 extending throughits length. Guide feature 651035 may include, in various embodiments,one or more guidewires (as shown), rails, impressions, lumens, tracks orthe like, any of which may facilitate guidance of a tissue modificationdevice 651032 along and/or through barrier device 651030. In variousembodiments, guide feature 651035 may comprise a separate device, notattached to barrier member 651030, as in the guidewire of FIGS. 226A and226B. Alternatively, one or more guide features 651035 may be attachedto, or integral with, barrier member 651030.

FIG. 227 shows an embodiment of a barrier device 651050 including acentral rail 651052 guide member along which a tissue modificationdevice 651054 may be guided. FIG. 228 shows an alternative embodiment ofa barrier device 651060 including a central rail 651062 guide memberalong which a tissue modification device 651064 may be guided. In someembodiments, barrier devices 651050, 651060 and tissue modificationdevices 651054, 651064 may be advanced through a delivery device 65601,while other embodiments may not employ such a delivery device 65601.

Referring to FIG. 229A, in one embodiment, a barrier device 651070 mayinclude a central channel 651072, accessible by a slit 651076, andmultiple flex grooves 651074. Multiple flex grooves 651074 mayfacilitate collapsing of barrier device 651070. In another embodiment,as in FIG. 229B, a barrier device 651080 may have a smooth, non-groovedsurface and a central channel 651082, accessible by a slit 651086. Slit651076, 651086 may facilitate coupling and decoupling of a tissuemodification device with barrier device 651070, 651080. Referring toFIGS. 229C-229E, in various alternative embodiments, central channels651072, 651082 may have any size or shape to allow passage of barrierdevices 651070, 651080 over any of a number of guide members 651090,651100, 651110 having variously shaped, protruding guide features651092, 651102, 651112.

In alternative embodiments, and with reference now to FIGS. 230A-230C,guide members 651120, 651130, 651140 may alternatively include variouslyshaped grooves, impressions or tracks 651122, 651132, 651142 foraccepting a protruding guide feature of a barrier device. FIGS.230D-230G show various embodiments of tissue modification devices651150, 651160, 651170, 651180, each having tissue modifying members651154, 651164, 651174, 651184 and a differently shaped protruding guidefeature 651152, 651162, 651172, 651182, such as a protrusion (FIGS.230D-230F) or groove (FIG. 230G). Guide features 651152, 651162, 651172,651182 may be used, in various embodiments, to facilitate guiding tissuemodification devices 651150, 651160, 651170, 651180 along one or moreguide members and/or barrier devices.

FIGS. 231A and 231B show two additional alternative embodiments ofbarrier devices 651190, 651200. Barrier device 651190 includes aprotruding central guide feature 651192, a flat tissue protectiveportion 651193, and lateral support members 651194. Barrier device651200 includes a central impression guide feature 651202, a flat tissueprotective portion 651203, and lateral support members 651204.

As described immediately above, in any of a number of differentembodiments, a barrier device may include one or more guide features.Such guide features may, in various embodiments, correspond with one ormore guide features on a guide device or guide member for guiding thebarrier member to a desired location and/or position in a patient.Alternative or additionally, one or more guide features on a barrierdevice may be used to facilitate guidance of one or more tissuemodification devices along, over and/or through the barrier device.Thus, in some embodiments, a barrier member may include multiple guidefeatures for guiding the barrier device and for guiding a tissuemodification device. In other embodiments, the same guide feature(s) ona barrier device may be used to guide both the barrier device and atissue modification device. Any suitable combination of guide feature(s)having any size, shape, pattern or the like may be used according tovarious embodiments.

FIG. 232 illustrates one embodiment of a delivery device 651210 fordelivering a barrier device 651220 to a location in a patient. In thisembodiment, barrier device 651220 includes a guidewire lumen 651221,through which a guidewire 651222 may extend, and a guide feature 651223,over which one or more tissue modification devices (not shown) may bepassed. Optionally, delivery device 651210 may include a visualizationlumen 651216, through which a visualization device may be passed, asuction lumen 651214, and an irrigation lumen 651216. In alternativeembodiments, delivery device 651210 many have any of a number ofsuitable different configurations and features. For example, in oneembodiment suction lumen 651214 and irrigation lumen 651216 may combinedinto one lumen, multiple visualization lumens 651216 may be included,and or the like.

As is mentioned above, in many of the described embodiments, a barrierdevice may include one or more pieces of material. Such material mayinclude any suitable material or combination, and in some embodimentsmay comprise a polymer, such as latex, rubber (viton), nylon, silicone,polyetheretherketone (PEEK), polyetherketoneketone (PEKK),polytetrafluoroethylene (PTFE), polyurethane (Tecothane), Pebax (co,USA), polycarbonate, Delrin (DuPont, USA), high-density polyethylene(HDPE), low-density polyethylene (LDPE), high-molecular weightpolyethylene (HMWPE), ultra-high-molecular weight polyethylene (UHMWPE),paraline coating, or the like. The material may be coated, laminated,impregnated, covered, or over-molded on a barrier device, oralternatively may be attached to a barrier device by adhesives orcements, thermal bonding techniques, with fasteners such as clasps orthread, or by forming pockets in the material which fit over ribs of thebarrier.

In other embodiments, one or more conductive wires may be included in abarrier device, such that the wires may be disposed and selectivelyactivated/exposed along either or both of a target tissue surface or anon-target tissue surface of the barrier device. In one embodiment, forexample, wires may be coupled with lateral support members of a barrierdevice. Conductive wires may be used, for example, to stimulate and thusidentify specific tissues, such as nerves, and/or to monitor theposition/location of the barrier device by measuring impedance and/orimparting electrical currents to induce stimulation to the targettissue. In one embodiment, an array of wire contact points along abarrier device may be implemented and independently activated to verifythat the barrier device is in a desired location/position.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. For example, in many of theembodiments described above, one or more abrasive tissue modifyingmembers may be substituted for one or more bladed tissue modifyingmembers or vice versa. These and many other modifications may be made tomany of the described embodiments. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

Articulating Tissue Cutting Device

The present invention relates generally to medical/surgical devices andmethods. More specifically, the present invention relates to a tissuecutting devices and methods.

A significant number of surgical procedures involve cutting, shaving,abrading or otherwise contouring or modifying tissue in a patient'sbody. As the demand for less invasive surgical procedures continuallyincreases, performing various tissue modifications such as cutting,contouring and removing tissue often becomes more challenging. Some ofthe challenges of minimally invasive procedures include working in asmaller operating field, working with smaller devices, and trying tooperate with reduced or even no direct visualization of the structure(or structures) being treated. For example, using arthroscopic surgicaltechniques for repairing joints such as the knee or the shoulder, it maybe quite challenging to cut certain tissues to achieve a desired result,due to the required small size of arthroscopic instruments, the confinedsurgical space of the joint, lack of direct visualization of thesurgical space, and the like. It may be particularly challenging in somesurgical procedures, for example, to cut or contour bone or ligamentoustissue with currently available minimally invasive tools and techniques.For example, trying to shave a thin slice of bone off a curved bonysurface, using a small-diameter tool in a confined space with little orno ability to see the surface being cut, as may be required in someprocedures, may be incredibly challenging or even impossible usingcurrently available devices.

Examples of less invasive surgical procedures include laparoscopicprocedures, arthroscopic procedures, and minimally invasive approachesto spinal surgery, such as a number of less invasive intervertebral discremoval, repair and replacement techniques. One area of spinal surgeryin which a number of less invasive techniques have been developed is thetreatment of spinal stenosis. Spinal stenosis occurs when one or moretissues in the spine impinges upon neural and/or neurovascular tissue,causing symptoms such as lower limb weakness, numbness and/or pain. Thisimpingement of tissue may occur in one or more of several differentareas in the spine, such as in the central spinal canal, or morecommonly in the lateral recesses of the spinal canal and/or one or moreintervertebral foramina.

FIGS. 1-234 show various partial views of the lower (lumbar) region ofthe spine. FIG. 1 shows an approximate top view of a vertebra with thecauda equina (the bundle of nerves that extends from the base of thespinal cord through the central spinal canal) shown in cross section andtwo nerve roots exiting the central spinal canal and extending throughintervertebral foramina on either side of the vertebra. The spinal cordand cauda equina run vertically along the spine through the centralspinal canal, while nerve roots branch off of the spinal cord and caudaequina between adjacent vertebrae and extend through the intervertebralforamina. Intervertebral foramina may also be seen in FIGS. 233 and 234,and nerves extending through the foramina may be seen in FIG. 233.

One common cause of spinal stenosis is buckling and thickening of theligamentum flavum (one of the ligaments attached to and connecting thevertebrae), as shown in FIG. 1. (Normal ligamentum flavum is shown incross section in FIG. 234) Buckling or thickening of the ligamentumflavum may impinge on one or more neurovascular structures, dorsal rootganglia, nerve roots and/or the spinal cord itself. Another common causeof neural and neurovascular impingement in the spine is hypertrophy ofone or more facet joints (or “zygopophaseal joints”), which providearticulation between adjacent vertebrae. (Two vertebral facet superiorarticular processes are shown in FIG. 1. Each superior articular processarticulates with an inferior articular process of an adjacent vertebrato form a zygopophaseal joint. Such a joint is labeled in FIG. 234.)Other causes of spinal stenosis include formation of osteophytes (or“bone spurs”) on vertebrae, spondylolisthesis (sliding of one vertebrarelative to an adjacent vertebra), facet joint synovial cysts, andcollapse, bulging or herniation of an intervertebral disc into thecentral spinal canal. Disc, bone, ligament or other tissue may impingeon the spinal cord, the cauda equina, branching spinal nerve rootsand/or blood vessels in the spine to cause loss of function, ischemiaand even permanent damage of neural or neurovascular tissue. In apatient, this may manifest as pain, impaired sensation and/or loss ofstrength or mobility.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% of adults aged 50 and older and is the most frequentreason cited for back surgery in patients aged 60 and older.Conservative approaches to the treatment of symptoms of spinal stenosisinclude systemic medications and physical therapy. Epidural steroidinjections may also be utilized, but they do not provide long lastingbenefits. When these approaches are inadequate, current treatment forspinal stenosis is generally limited to invasive surgical procedures toremove ligament, cartilage, bone spurs, synovial cysts, cartilage, andbone to provide increased room for neural and neurovascular tissue. Thestandard surgical procedure for spinal stenosis treatment includeslaminectomy (complete removal of the lamina (see FIGS. 1 and 233) of oneor more vertebrae) or laminotomy (partial removal of the lamina),followed by removal (or “resection”) of the ligamentum flavum. Inaddition, the surgery often includes partial or occasionally completefacetectomy (removal of all or part of one or more facet joints). Incases where a bulging intervertebral disc contributes to neuralimpingement, disc material may be removed surgically in a discectomyprocedure.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the effected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. In a spinal fusion procedure, the vertebrae are attached togetherwith some kind of support mechanism to prevent them from moving relativeto one another and to allow adjacent vertebral bones to fuse together.Unfortunately, a surgical spine fusion results in a loss of ability tomove the fused section of the back, diminishing the patient's range ofmotion and causing stress on the discs and facet joints of adjacentvertebral segments. Such stress on adjacent vertebrae often leads tofurther dysfunction of the spine, back pain, lower leg weakness or pain,and/or other symptoms. Furthermore, using current surgical techniques,gaining sufficient access to the spine to perform a laminectomy,facetectomy and spinal fusion requires dissecting through a wideincision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Discectomy procedures require entering through an incision in thepatient's abdomen and navigating through the abdominal anatomy to arriveat the spine. Thus, while laminectomy, facetectomy, discectomy, andspinal fusion frequently improve symptoms of neural and neurovascularimpingement in the short term, these procedures are highly invasive,diminish spinal function, drastically disrupt normal anatomy, andincrease long-term morbidity above levels seen in untreated patients.Although a number of less invasive techniques and devices for spinalstenosis surgery have been developed, these techniques still typicallyrequire removal of significant amounts of vertebral bone and, thus,typically require spinal fusion.

Therefore, it would be desirable to have less invasive methods anddevices for cutting, shaving, contouring or otherwise modifying targettissue in a spine to help ameliorate or treat spinal stenosis, whilepreventing unwanted effects on adjacent or nearby non-target tissues.Ideally, such techniques and devices would reduce neural and/orneurovascular impingement without removing significant amounts ofvertebral bone, joint, or other spinal support structures, therebyavoiding the need for spinal fusion and, ideally, reducing the long-termmorbidity levels resulting from currently available surgical treatments.It may also be advantageous to have tissue cutting devices capable oftreating target tissues in parts of the body other than the spine, whilepreventing damage of non-target tissues. At least some of theseobjectives will be met by the present invention.

Various embodiments of an articulating tissue cutting device formodifying tissue in a patient are provided. Although portions of thefollowing description and accompanying drawing figures generally focuson cutting tissue in a spine, in various embodiments, any of a number oftissues in other anatomical locations in a patient may be modified.

Referring to FIG. 235A, one embodiment of articulating rongeur 70210 mayinclude a shaft having a proximal portion 70211, a distal portion 70232,and an articulation feature 70230 (or “articulation member”) between thetwo. A handle 70216 with a squeezable trigger 70219 and a dial 70217 maybe coupled with proximal shaft portion 70211. A proximal blade 70226 anda distal blade 70228 may be disposed along distal shaft portion 70232.In some embodiments, both proximal shaft portion 70211 and distal shaftportion 70232 are predominantly rigid. In alternative embodiments,distal shaft portion 70232 may be more flexible than proximal portion70211 or may be largely rigid but may have one or more flexible portionsdisposed along its length. Proximal shaft portion 70211 may include aproximal stationary portion 70212 a coupled with or extending fromproximal handle 70216, a distal stationary portion 70212 b, and amovable shaft portion 70214. Articulation feature 70230 may include anysuitable mechanism, such as one or more slits, grooves, hinges, jointsand/or combinations of materials, to allow distal portion 70232 toarticulate relative to proximal portion 70211. As mentioned above,“articulate” includes articulating about a joint, as well as bending,flexing, angling and the like. Distal shaft portion 70232 may include aportion that extends underneath and between blades 70226, 70228, whichmay be referred to as a “substrate,” “platform” or “extension” herein.

In one embodiment, at least two flexible wires 70224 (or “wirebundle”—see FIG. 235D) may slidably extend through a portion of proximalshaft portion 70211 and distal shaft portion 70232 so that their distalends attach to proximal blade 70226. Optionally, wires 70224 may bebundled together along their entire lengths or along part of theirlengths, and such a wire bundle may be partially housed within a wirebundle tube 70218, which may slidably pass through distal stationaryshaft portion 70212 b. In use, trigger 70219 may be squeezed(double-headed, solid-tipped arrow) to advance moveable shaft portion70214, which advances wire bundle tube 70218 and wires 70224, thusadvancing proximal blade 70226 toward stationary blade 70228 to cuttissue.

In some embodiments, articulating rongeur 70210 may be advanced into apatient's back through an incision 70220, which is shown in FIG. 235A asan open incision but which may be a minimally invasive or less invasiveincision in alternative embodiments. Rongeur 70210 may be advanced intothe patient in a relatively straight configuration and then articulate(or “flexed” or “bent”) at articulation feature 70230 to facilitatepassing at least part of distal shaft portion 70232 into anintervertebral foramen (IF). In some embodiments, an articulating memberon handle 70216, such as dial 70217, may be used to apply a force to aflexing member extending from dial 70217 to at least articulationfeature 70230. The ability of rongeur 70210 to articulate aboutarticulation feature 70230 may facilitate passage of rongeur 70210between tissues in hard-to-reach or tortuous areas of the body, such asbetween a nerve root (NR) and facet joint and into an intervertebralforamen (IF). Generally, rongeur 70210 may be advanced to a positionsuch that blades 70226, 70228 face tissue to be cut in a tissue removalprocedure (“target tissue”) and one or more non-cutting surfaces ofrongeur 70210 face non-target tissue, such as nerve and/or neurovasculartissue. In the embodiment shown in FIG. 235A, blades 70226, 70228 arepositioned to cut ligamentum flavum (LF) and may also cut hypertrophiedbone of the facet joint, such as the superior articular process (SAP).(Other anatomical structures depicted in FIG. 235A include the vertebra(V) and cauda equina (CE)).

Once rongeur 70210 is advanced into the patient to position distalportion 70232 at least partway into an intervertebral foramen,articulation feature 70230 may be locked into position, either by alocking mechanism in articulation feature 70230 itself or alternativelyor additionally by a locking mechanism in handle 70216, such as amechanism coupled with or part of dial 70217. Once articulation feature70230 is locked, handle 7016 may be pulled (hollow-tipped arrow) to pulldistal shaft portion 70232 against target tissue and thus to urge thecutting portion of rongeur 70210 (e.g., blades 70226, 70228) againstligamentum flavum (LF), superior articular process (SAP), and/or othertarget tissue to be cut. Handle 70216 may then be actuated, such as bysqueezing in the embodiment shown, which advances moveable shaft 70214,thus advancing wire bundle tube 70218, flexible wires 70224 and proximalblade 70226, to cut tissue between proximal blade 70226 and distal blade70228. Handle 70216 may be released and squeezed as many times asdesired to remove a desired amount of tissue. When a desired amount oftissue has been cut (or at any point during a tissue cutting procedureto monitor progress), rongeur 70210 may be removed from the patient'sback.

As mentioned previously, and as described in greater detail below, invarious embodiment articulation feature 70230 may take any of a numberof different forms and may generally include any suitable feature orfeatures to allow rongeur 70210 to flex or be flexed. In variousembodiments, articulation feature 70230 may include one or more hinges,slits, grooves, joints, materials having varying levels ofcompressibility or the like.

Referring now to FIGS. 235B-235D, the articulating and blade advancingfunctions of articulating rongeur 70210 are demonstrated. FIG. 235Bshows articulating rongeur 70210 in its generally straightconfiguration. In one embodiment, as shown in FIG. 235C, dial 70217 maybe turned (hollow-tipped arrow) to articulate distal portion 70232. Withdistal portion 70232 articulated, as shown in FIG. 235D, trigger 70219may be squeezed (hollow-tipped arrow) to advance moveable shaft portion70214, which in turn advances wires 70224 and proximal blade 70226toward distal blade 70228 to cut target tissue. In some embodiments,proximal blade 70226 may be advanced while rongeur is in its straight orarticulated configuration. In some embodiments, rongeur 70210 mayarticulate in increments, such as from a straight configuration to afirst flexed configuration to a second flexed configuration and so on.Also in some embodiments, articulation feature 70230 may automaticallylock into an articulated position. In alternative embodiments,articulation feature 70230 may be manually locked, such as by lockingdial 70217 or the like.

For further detail regarding a multi-wire tissue cutter device, many ofthe features of which may be incorporated into articulating rongeur70210, reference may be made to U.S. patent application Ser. No.11/461,740, titled “Multi-Wire Tissue Cutter,” and filed on Aug. 1,2006, now Publication No. US-2008-0051812-A1, the full disclosure ofwhich is hereby incorporated by reference. In alternative embodiments,different tissue cutting mechanisms may be included in articulatingrongeur 70210. For example, in one embodiment, distal blade 70228 may betranslatable and proximal blade 70226 may be stationary. In analternative embodiment, distal blade 70228 and proximal blade 70226 maybe translated toward one another to cut tissue. A number of such bladedtissue cutting mechanisms are described, for example, in U.S. patentapplication Ser. No. 11/405,848, titled “Mechanical Tissue ModificationDevices and Methods,” and filed on Apr. 17, 2006, now Publication No.US-2012-0078253-A9, the full disclosure of which is hereby incorporatedby reference. In further alternative embodiments, some of which aredescribed in greater detail below, blades 70226, 70228 may be replacedaltogether by a different tissue cutting mechanism, such as but notlimited to one or more abrasive surfaces, files, rasps, saws, planes,electrosurgical devices, bipolar electrodes, monopolar electrodes,thermal electrodes, cold ablation devices, rotary powered mechanicalshavers, reciprocating powered mechanical shavers, powered mechanicalburrs, lasers, ultrasound devices, cryogenic devices, and/or water jetdevices

Generally, proximal shaft portion 70211 and distal shaft portion 70232may be formed of any suitable material, such as but not limited tostainless steel. Wire bundle 70224 extends through at least part of wiretube 70218, through distal stationary shaft portion 70212 b, and in someembodiments through part of distal shaft portion 70232, and is coupledwith proximal blade 70226. Wire tube 70218 acts to secure the proximalend of wire bundle 70224, such as by crimping, welding or the like. Inalternative embodiments, wire tube 70218 may be excluded, and theproximal end of wire bundle 70224 may be otherwise coupled with device.For example, in various embodiments, wire bundle 70224 may be coupledwith moveable shaft portion 70214, may be movably coupled with handle70216, or the like. In the side view of FIG. 235D, wire bundle 70224appears as a single wire, in this embodiment due to the fact that distalshaft portion 70232 flattens wire bundle 70224 to a one-wire-thick crosssection.

In various embodiments, proximal shaft portion 70211 and distal shaftportion 70232 may have any suitable shapes and dimensions and may bemade of any suitable materials. For example, in various embodiments,shaft portions 70211, 70232 may be made from any of a number of metals,polymers, ceramics, or composites thereof. Suitable metals, for example,may include but are not limited to stainless steel (303, 304, 316,316L), nickel-titanium alloy, tungsten carbide alloy, or cobalt-chromiumalloy, for example, Elgiloy® (Elgin Specialty Metals, Elgin, Ill., USA),Conichrome® (Carpenter Technology, Reading, Pa., USA), or Phynox® (ImphySA, Paris, France). Suitable polymers include but are not limited tonylon, polyester, Dacron®, polyethylene, acetal, Delrin® (DuPont,Wilmington, Del.), polycarbonate, nylon, polyetheretherketone (PEEK),and polyetherketoneketone (PEKK). In some embodiments, polymers may beglass-filled to add strength and stiffness. Ceramics may include but arenot limited to aluminas, zirconias, and carbides.

Portions of shaft 70211, 70232 through which wire bundle 70224 travelswill generally be predominantly hollow, while other portions may beeither hollow or solid. For example, in one embodiment, moveable shaftportion 70214 and proximal stationary portion 70212 a may be solid, anddistal stationary portion 70212 b and part of distal portion 70232 maybe hollow. Although one particular embodiment of a shaft mechanism formoving wire bundle 70224 is shown, various embodiments may employ any ofa number of alternative mechanisms.

Wire bundle 70224 may include as few as two flexible wires 70224 and asmany as one hundred or more wires 70224. In some embodiments, forexample, between three and 20 wires 70224 may be used, and even morepreferably, between four and ten wires 70224. Wires 70224 may have anyof a number of different diameters, so in some embodiments the number ofwires 70224 used may be determined by the diameter of wire 70224 used.In various embodiments, each wire 70224 may be a solid wire, a braidedwire, a core with an outer covering or the like, and may be made of anysuitable material. For example, in various embodiments, wires 70224 maybe made from any of a number of metals, polymers, ceramics, orcomposites thereof. Suitable metals, for example, may include but arenot limited to stainless steel (303, 304, 316, 316L), nickel-titaniumalloy, tungsten carbide alloy, or cobalt-chromium alloy, for example,Elgiloy® (Elgin Specialty Metals, Elgin, Ill., USA), Conichrome®(Carpenter Technology, Reading, Pa., USA), or Phynox® (Imphy SA, Paris,France). In some embodiments, materials for the wires 70224 or forportions or coatings of the wires may be chosen for their electricallyconductive or thermally resistive properties. Suitable polymers includebut are not limited to nylon, polyester, Dacron®, polyethylene, acetal,Delrin® (DuPont, Wilmington, Del.), polycarbonate, nylon,polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). In someembodiments, polymers may be glass-filled to add strength and stiffness.Ceramics may include but are not limited to aluminas, zirconias, andcarbides. In some embodiments, all wires 70224 may be made of the samematerial, whereas in alternative embodiments, wires 70224 may be made ofdifferent materials. Individual wires 70224 may also have any length,diameter, tensile strength or combination of other characteristics andfeatures, according to various embodiments, some of which are discussedin greater detail below.

In various embodiments, flexible wires 70224 may be bound or otherwisecoupled together at one or more coupling points or along the entirelength of wire bundle 70224. In one embodiment, for example, wires 70224may be coupled together by a sleeve or coating overlaying wire bundle70224. In another embodiment, wires 70224 may only be coupled togetherat or near their proximal ends, at or near their connection point totube 70218, moveable shaft portion 70214 or the like. In an alternativeembodiment, wires 70224 may be individually coupled with an actuator,such as handle 70216, and not coupled to one another directly. In anycase, wires 70224 will typically be able to move at least somewhat, suchas laterally, relative to one another.

In some embodiments, wire bundle 70224 may include one or more elongate,flexible members for performing various functions, such as enhancingtissue cutting, visualizing a target area or the like. For example, invarious embodiments, wire bundle 70224 may include one or more opticalfibers, flexible irrigation/suction tubes, flexible high pressure tubes,flexible insulated tubing for carrying high temperature liquids,flexible insulated tubing for carrying low temperature liquids, flexibleelements for transmission of thermal energy, flexible insulated wiresfor the transmission of electrical signals from a sensor, flexibleinsulated wires for the transmission of electrical signals towards thedistal end of the wires, energy transmission wires, or some combinationthereof. Examples of visualization devices that may be used includeflexible fiber optic scopes, CCD (charge-coupled device) or CMOS(complementary metal-oxide semiconductor) chips at the distal end offlexible probes, LED illumination, fibers or transmission of an externallight source for illumination or the like.

When blades 70226, 70228 face target tissue to be modified, such asbuckled, thickened or otherwise impinging ligamentum flavum tissue,rongeur 70210 is configured such that an atraumatic surface (or multipleatraumatic surfaces) of the distal shaft portion 70232 faces non-targettissue. Distal shaft portion 70232 may thus act as a tissue protectivesurface and in various embodiments may have one or more protectivefeatures, such as a width greater than the width of blades 70226, 70228,rounded edges, bumpers made of a different material such as a polymer,protective or lubricious coating(s), extendable or expandable barriermember(s), drug-eluting coating or ports, or the like. In someinstances, distal shaft portion 70232 may include one or more“non-tissue-modifying” surfaces, meaning that such surfaces may notsubstantially modify the non-target tissue. In alternative embodiments,distal shaft portion 70232 may affect non-target tissue by protecting itin some active way, such as by administering one or more protectivedrugs, applying one or more forms of energy, providing a physicalbarrier, or the like.

Generally, blades 70226, 70228 may be disposed on distal shaft portion70232. Proximal blade 70226 may be unattached or moveably/slidablyattached to distal shaft portion 70232, so that it is free to translate(or “reciprocate”) along distal shaft portion 70232 with the back andforth movement of wire bundle 70224. In one embodiment, for example,proximal blade 70226 may be slidably coupled with distal shaft portion70232 via a piece of material wrapped around blade 70226 and distalshaft portion 70232. In another embodiment, proximal blade 70226 mayslide through one or more tracks on distal shaft portion 70232. Distalblade 70228 may be fixedly attached to distal shaft portion 70232 andthus remain stationary, relative to distal shaft portion 70232, suchthat proximal blade 70226 translates toward stationary distal blade70228 to cut tissue. In alternative embodiments, the distal end of wirebundle 70224, itself, may be used to cut tissue, and rongeur 70210 maythus not include proximal blade 70226. For example, each wire 70224 mayhave a sharp, tissue cutting point, or wire bundle 70224 as a whole mayform a sharp, tissue cutting edge. The distal end of wire bundle 70224may advance toward distal blade 70228 to cut target tissue, or inalternative embodiments, wire bundle 70224 may advance toward anon-sharp backstop to cut tissue or may simply advance against tissue toablate it, without pinching the tissue between the wire bundle 70224distal end and any other structure. An example of the latter of theseembodiments might be where ultrasound energy is used to reciprocate wirebundle 70224, in which case the reciprocation of wire bundle 70224 maybe sufficient to cut or ablate tissue, without pinching or snippingbetween wire bundle and another structure.

In various embodiments, blades 70226, 70228, or other cutting structuressuch as the distal ends of wire bundle 70224, a backstop or the like,may be disposed along any suitable length of distal shaft portion 70232.In the embodiment shown in FIG. 236A, for example, blades 70226, 70228are disposed along a length of distal shaft portion 70232. In analternative embodiment, distal shaft portion 70232 may comprise a hollowportion through which wire bundle 70224 travels and a window throughwhich wire bundle 70224 is exposed. In any case, blades 70226, 70228 orother cutting members may be disposed or exposed along a desired lengthof rongeur 70210, to help limit an area in which the cutting members areactive, thus helping to limit the exposure of non-target tissues to suchcutting elements. In one embodiment, for example, such as an embodimentof the device to be used in a spinal treatment, blades 70226, 70228 maybe disposed along a length of distal shaft portion 70232 measuring nolonger than about 10 cm, and preferably no more than about 6 cm, andeven more preferably no more than about 3 cm. In various embodiments,the length along which blades 70226, 70228 are disposed may be selectedto approximate a length of a specific anatomical treatment area.

Blades 70226, 70228 may be made from any suitable metal, polymer,ceramic, or combination thereof. Suitable metals, for example, mayinclude but are not limited to stainless steel (303, 304, 316, 316L),nickel-titanium alloy, tungsten carbide alloy, or cobalt-chromium alloy,for example, Elgiloy® (Elgin Specialty Metals, Elgin, Ill., USA),Conichrome® (Carpenter Technology, Reading, Pa., USA), or Phynox® (ImphySA, Paris, France). In some embodiments, materials for blades 70226,70228 or for portions or coatings of blades 70226, 70228 may be chosenfor their electrically conductive or thermally resistive properties.Suitable polymers include but are not limited to nylon, polyester,Dacron®, polyethylene, acetal, Delrin® (DuPont, Wilmington, Del.),polycarbonate, nylon, polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK). In some embodiments, polymers may beglass-filled to add strength and stiffness. Ceramics may include but arenot limited to aluminas, zirconias, and carbides. In variousembodiments, blades 70226, 70228 may be manufactured using metalinjection molding (MIM), CNC machining, injection molding, grindingand/or the like. Proximal and distal blades 70226, 70228 may be attachedto wire bundle 70224 and distal shaft portion 70232, respectively, viaany suitable technique, such as by welding, adhesive or the like.

In some embodiments, articulating rongeur 70210 may include a tissuecollection chamber 70229 distal to distal blade 70228. For example,distal blade 70228 may be hollow and in fluid communication with tissuecollection chamber 70229, such that when tissue is cut using blades,70226, 70228, at least some of the tissue passes under distal blade70228 and into collection chamber 70229. Tissue collection chamber 70229may be made of any suitable material, such as but not limited to any ofthe materials listed above for making blades 70226, 70228. In oneembodiment, for example, chamber 70229 may comprise a layer of polymericmaterial attached between distal blade 70228 and distal shaft portion70232. In another embodiment, collection chamber 70229 and distal blade70228 may comprise one continuous piece of material, such as stainlesssteel. Generally, distal blade 70228 and chamber 70229 form a hollow,continuous space into which at least a portion of cut tissue may passafter it is cut.

With reference now to FIGS. 236A and 236B, a portion of an articulatingrongeur 70250, according to one embodiment, may include a shaft 70251having a longitudinal axis 70258, a proximal shaft portion 70252, adistal shaft portion 70254, and an articulation feature 70256 betweenthe proximal and distal portions 70252, 70254. Rongeur 70250 may alsoinclude a proximal blade 70262 and a distal blade 70264 disposed on thedistal shaft portion 70254. (In FIGS. 236A and 236B, mechanism formoving one or both of blades 70262, 70264 is omitted, to enhance theclarity of the drawing figures.) Rongeur 70250 may further include oneor more tensioning wires 70260, extending from a handle at the proximalend of rongeur 70250 (not shown), through proximal shaft portion 70252,to an attachment point 70261 in or on distal shaft portion 70254.

Tensioning wire 70260 generally extends through and is attached to shaft70251 closer to the top/blade side than the bottom/opposite side,relative to longitudinal axis 70258. When tensioning wire 70260 ispulled proximally, as depicted by the hollow-tipped arrow in FIG. 236B,shaft 70251 articulates, bends or flexes toward the blade side of shaft70251 by articulating at articulation feature 70256. In variousembodiments, articulation feature 70256 may include any suitable numberof slits, grooves, hinges, joints or the like. In one embodiment, forexample, articulation feature 70256 may include two materials onopposite sides of shaft 70251, with a more easily compressible materiallocated on the top side (or blade side) of articulation feature 70256and a less easily compressible material located on the opposite/bottomside.

In some embodiments, tensioning wire 70260 may extend only to a distalside of articulation feature 70256 and attach there, rather thanextending into distal shaft portion 70254. Alternatively, tensioningwire 70260 may extend farther distally on distal portion 70254, toattach at a point at or near distal blade 70264 or even at or near theextreme distal end of shaft 70251. In such cases, a sufficient amount oftensioning force applied to tensioning wire 70260 may cause distalportion 70254 to curl or bend in the direction of the blade side ofshaft 70251. If distal portion 70254 is made of a relatively rigidmaterial, such bending may be minimal, while if distal portion 70254 ismade of a more flexible material, such bending may be more significant.In some cases, such bending may facilitate passage of distal portion70254 around a curved surface, through an anatomical curved passagebetween tissues, or the like. For example, in some embodiments, distalshaft portion 70254 may be made of a relatively flexible material, whichmay facilitate its passage into a small space, between tissues or thelike. Applying tensioning force via tensioning wire 70260 may, in suchan embodiment, not only articulate shaft 70251 at articulation feature70256, but may also stiffen or rigidify distal portion 70254, so thatdevice 70250 may be pulled back to urge the stiffened/rigidified distalportion 70254 against target tissue.

Tensioning wire 70260 generally comprises a high-strength wire, cable,cord or the like and may be made of any suitable material. In oneembodiment, for example, tensioning wire 70260 may be made of carbonfiber. Other suitable metals from which tensioning wires 70260 may beconstructed may include but are not limited to stainless steel (303,304, 316, 316L), nickel-titanium alloy, tungsten carbide alloy, orcobalt-chromium alloy, for example, Elgiloy® (Elgin Specialty Metals,Elgin, Ill., USA), Conichrome® (Carpenter Technology, Reading, Pa.,USA), or Phynox® (Imphy SA, Paris, FranceSuitable polymers include butare not limited to nylon, polyester, Dacron®, polyethylene, acetal,Delrin® (DuPont, Wilmington, Del.), polycarbonate, nylon,polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). In someembodiments, polymers may be glass-filled to add strength and stiffness.Ceramics may include but are not limited to aluminas, zirconias, andcarbides.

In various embodiments, any number of tensioning wires 70260 may beused, such as between one and 100 wires 70260. In cases where multiplewires 70260 are used, it may be possible in some embodiments to furthersteer distal shaft portion 70254 by individually manipulating one ormore wires 70260 relative to other wires. In one embodiment, tensioningwires 70260 may extend through a lumen of shaft 70251 and may beattached at attachment point 70261 via any suitable means, such asadhesive, welding, crimping, pressure fitting or the like. In someembodiments, tensioning wire 70260 may be sufficiently strong that anamount of tensioning force may be applied that can bend distal portion70254 and/or render distal portion 70254 more stiff or rigid.

In an alternative embodiment, and with reference now to FIGS. 237A and237B, a portion of an articulating rongeur 70270 may include a shaft70271 having a longitudinal axis 70278, a proximal shaft portion 70272,a distal shaft portion 70274, and an articulation feature 70275including multiple flex slits 70276. Rongeur 70270 may also include aproximal blade 70282 and a distal blade 70284 disposed on the distalshaft portion 70274. (Again, in FIGS. 237A and 237B, mechanism formoving one or both of blades 70282, 70284 is omitted, to enhance theclarity of the drawing figures.) Rongeur 70270 may further include oneor more compression members 70280, extending from a handle at theproximal end of rongeur 70270 (not shown), through proximal shaftportion 70272, to at least articulation feature 70275, and in someembodiments (as in FIGS. 237A and 237B) to an attachment point 70281 indistal shaft portion 70274.

As described above, in various embodiments, articulation feature 70275may include any suitable number of flex slits 70276, grooves, hinges,joints, differing materials or the like. Compression member 70280extends through shaft 70271 closer to the bottom/opposite side than thetop/blade side, relative to longitudinal axis 70278. When compressive(or “pushing”) force is applied to compression member 70280, as depictedby the hollow-tipped arrow in FIG. 237B, shaft 70271 bends or flexestoward the blade side of shaft 70271 by bending/flexing at articulationfeature 70275.

In some embodiments, compression member 70280 may extend only to adistal side of articulation feature 70275 and attach there, rather thanextending into distal shaft portion 70274. Alternatively, compressionmember 70280 may extend farther distally on distal portion 70274, toattach at a point at or near distal blade 70284 or even at or near theextreme distal end of shaft 70271. In such cases, a sufficient amount ofcompressive force applied to compression member 70280 may cause distalportion 70274 to curl or bend in the direction of the blade side ofshaft 70271. If distal portion 70274 is made of a relatively rigidmaterial, such bending may be minimal, while if distal portion 70274 ismade of a more flexible material, such bending may be more significant.In some cases, such bending may facilitate passage of distal portion70274 around a curved surface, through an anatomical curved passagebetween tissues, or the like. For example, in some embodiments, distalshaft portion 70274 may be made of a relatively flexible material, whichmay facilitate its passage into a small space, between tissues or thelike. Applying tensioning force via compression member 70280 may, insuch an embodiment, not only articulate shaft 70271 at articulationfeature 70275, but may also stiffen or rigidify distal portion 70274, sothat device 70270 may be pulled back to urge the stiffened/rigidifieddistal portion 70274 against target tissue.

Compression member 70280 may generally comprise any of a number of forcetransmitting members, such as one or more high-strength wires, amaterial substrate, a column of fluid or the like. A wire, substrate orother solid compression member 70280 may be made of any suitablematerial, such as but not limited to carbon fiber, stainless steel (303,304, 316, 316L), nickel-titanium alloy, tungsten carbide alloy, orcobalt-chromium alloy, for example, Elgiloy® (Elgin Specialty Metals,Elgin, Ill., USA), Conichrome® (Carpenter Technology, Reading, Pa.,USA), or Phynox® (Imphy SA, Paris, FranceSuitable polymers include butare not limited to nylon, polyester, Dacron®, polyethylene, acetal,Delrin® (DuPont, Wilmington, Del.), polycarbonate, nylon,polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). In someembodiments, polymers may be glass-filled to add strength and stiffness.Ceramics may include but are not limited to aluminas, zirconias, andcarbides.

In various embodiments, any number of compression members 70280 may beused, such as between one and 100 compression wires or the like. Incases where multiple compression members 70280 are used, it may bepossible in some embodiments to further steer distal shaft portion 70274by individually manipulating one or more compression members 70280relative to others. In one embodiment, compression member 70280 mayextend through a lumen of shaft 70271 and may be attached at attachmentpoint 70281 via any suitable means, such as adhesive, welding, crimping,pressure fitting or the like. In one embodiment, for example,compression member 70280 may abut a structure such as a backstop, screwdrive or the like. In some embodiments, compression member 70280 may besufficiently strong that an amount of tensioning force may be appliedthat can bend distal portion 70274 and/or render distal portion 70274more stiff or rigid.

In one alternative embodiment (not shown), a rongeur may include bothone or more tensioning members 70260 and one or more compression members70280. In such an embodiment, both tensioning and compression force maybe applied to the rongeur to flex its shaft at one or more locationsalong its length.

Referring now to FIG. 238 a, another embodiment of an articulatingrongeur 70290 is shown in cross-section. Articulating rongeur 70290 (ofwhich only a portion is shown) may include a shaft 70291 having aproximal shaft portion 70292, a distal shaft platform 70240 (or“substrate” or “extension”), and an articulation feature 70296. Rongeur70290 may also include a proximal blade 70302, slidably disposed onplatform 70240 and coupled with a blade actuating wire 70306 thatextends through proximal shaft portion 70292 and out an aperture 70308therein. A distal blade 70304 may be fixedly attached to platform 70240,and a tissue capture member 70305 may be disposed between distal blade70304 and platform 70240 to capture cut tissue that passes under blade70304. Rongeur 70290 may further include one or more compression members70300, as described above in reference to FIGS. 237A and 237B.Compressive force may be applied to compression member 70300(hollow-tipped arrow) to articulate rongeur 70290 about articulationfeature 70296, and blade articulating wire 70306 may be advanced toadvance proximal blade 70302 (solid-tipped arrows) to cut tissue.

In various embodiments, platform 70240 may comprise an extension of alower surface of proximal shaft portion 70292. Alternatively oradditionally, platform 70240 may comprise one or more separate pieces ofmaterial coupled with proximal shaft portion 70292, such as by weldingor attaching with adhesive. Platform 70240 may comprise the same ordifferent material(s) as proximal shaft portion 70292, according tovarious embodiments, and may have any of a number of configurations. Forexample, platform 70240 may comprise a flat, thin, flexible strip ofmaterial (such as stainless steel). In an alternative embodiment,platform 70240 may have edges that are rounded up to form a trackthrough which proximal blade 70302 may travel. In some embodiments,platform 70240 may be flexible, allowing it to bend, while in otherembodiments, platform 70240 may be predominantly rigid, so that it doesnot bend or bends only slightly when compressive force is applied tocompressive member 70300. In various embodiments, platform 70240 may bemade more rigid by making platform 70240 more think and/or by using morerigid material to construct platform 70240. In some embodiments,platform 70240 may be made of a shape memory material and given a curvedshape, while in other embodiments platform 70240 may be rigid and curvedor rigid and straight. Differently shaped platforms 70240 and/orplatforms 70240 having different amounts of flexibility may facilitateuse of different embodiments of rongeur 70290 in different locations ofthe body. A more rigid platform 70240, for example, may facilitatecutting of a hard material such as bone with blades 70302, 70304.

Some embodiments of rongeur 70290 may further include one or moreelectrodes coupled with platform 70240, for transmitting energy totissues and thereby confirm placement of rongeur 70290 between targetand non-target tissues. For example, one or more electrodes may beplaced on a lower surface of platform 70240, and the electrode(s) may bestimulated to help confirm the location of neural tissue relative toblades 70302, 70304. In such embodiments, nerve stimulation may beobserved as visible and/or tactile muscle twitch and/or byelectromyography (EMG) monitoring or other nerve activity monitoring. Invarious alternative embodiments, additional or alternative devices forhelping position, use or assess the effect of rongeur 70210 may beincluded. Examples of other such devices may include one or more neuralstimulation electrodes with EMG or SSEP monitoring, ultrasound imagingtransducers external or internal to the patient, a computed tomography(CT) scanner, a magnetic resonance imaging (MRI) scanner, a reflectancespectrophotometry device, and a tissue impedance monitor disposed acrossa bipolar electrode tissue modification member or disposed elsewhere onrongeur 70210.

Referring now to FIGS. 238 b and 238 c, a side view (FIG. 238 b) and anend-on view (FIG. 238 c) of a portion 70200 of rongeur 70290 (circled inFIG. 238 a) are shown. (FIG. 238 c is a view from the perspectivelabeled A in FIG. 238 b.) It has been found that in some embodiments,various components and portions of tissue cutting rongeur 70290 maypreferably have a combination of dimensions that facilitate passage intoa small space and effective tissue cutting. In various embodiments, thedimensions described below may be applied to any tissue cutting device,especially devices designed to cut tissue located in small anatomicalpassageways or spaces, such as in and around an intervertebral foramenof a spine. For example, a number of alternative tissue cutting devicesare described in U.S. patent application Ser. No. 11/405,848, entitled“Mechanical Tissue Modification Devices and Methods”, and filed Apr. 17,2006, now Publication No. US-2012-0078253-A9, the full disclosure ofwhich is hereby incorporated by reference. In that disclosure, forexample, one of the embodiments a tissue cutting device includes atranslatable blade that is retracted via two pull wires. It iscontemplated that the dimensional characteristics described below may beapplied to such a device, as well as to other tissue cutting devices inother alternative embodiments.

Referring again to FIGS. 238 b and 238 c, in one embodiment, platform70240 (or “substrate”) may have a substrate height 70202 (or“thickness”), blades 70302, 70304 may have a blade height 70204, edgesof blades 70302, 70304 may be separated by a blade opening distance70205, blades 70302, 70304 may have a blade width 70207, platform 70240may have a substrate width 70206, and each blade 7026, 7028 togetherwith platform 70240 may have a total device height 70208. (Substrateheight 70202 or substrate width 70206 may also be referred to as theheight or width of “a portion of the shaft immediately below theblade(s).”) Each of these various dimensions may be adjusted accordingto various embodiments and for various applications to different partsof patient anatomy. Some embodiments, for example, may be configured foruse in and near an intervertebral foramen of a spine. In an alternativeembodiment, dimensions of rongeur 70290 may be selected for use in ashoulder surgery procedure, a knee surgery procedure, a hand surgeryprocedure or the like.

In some embodiments, the portion 70200 of rongeur 70290 may have anoverall size and dimensions such that it may be passed into an epiduralspace of a spine and at least partially into an intervertebral space ofthe spine, so that it may be used to cut ligament and/or bone in thespine to treat neural and/or neurovascular impingement. In someembodiments, for example, substrate height 70202 may be less than bladeheight 70204. In other words, the ratio of substrate height 70202 toblade height may be approximately less than one, and in some embodimentsapproximately less than or equal to %. In these or other embodiments,total height 70208 (of blade 70302 and platform 70240) may be less thansubstrate width 70206 and/or blade width 70207. (In some embodiments,substrate width 70206 may be approximately equal to blade width 70207,as shown, while in alternative embodiments, substrate width 70206 may begreater than blade width 70207.) In other words, the ratio of totalheight 70208 to width 70207 may be approximately less than one, and insome embodiments approximately less than or equal to %. In someembodiments, rongeur 70290 may have a combination of a ratio ofsubstrate height 70202 to blade height approximately less than one and aratio of total height 70208 to width 70206 approximately less than one.Such a configuration is contrary to that of traditional rongeurs, whichinclude cutting blades thinner than their underlying supportingstructure and which have a total height greater than the width of thedevice. In one embodiment, for example, blade opening distance 70205 maybe between about 0.1 inches and about 0.5 inches, substrate height 70202may be between about 0.010 inches and about 0.050 inches, blade height70204 may be between about 0.010 inches and about 0.075 inches, andblade width 70207 may be between about 0.2320 and about 0.400 inches.More preferably, in one embodiment, blade opening distance 70205 may bebetween about 0.3 inches and about 0.35 inches, substrate height 70202may be between about 0.025 inches and about 0.035 inches, blade height70204 may be between about 0.040 inches and about 0.060 inches, andblade width 70207 may be between about 0.165 and about 0.250 inches. Inalternative embodiments, such as for use in other parts of the body,rongeur 70290 may have any of a number of different combinations ofdimensions.

To optimize rongeur 70290 for any of a number of possible uses, thedimensions described above may be combined with any of a number ofmaterials for the various components of rongeur 70290. Examples of suchmaterials for blades 70302, 70304, platform 70240 and the like have beenlisted previously. In some embodiments, for example, platform 70240 maybe made of a material and may have a height or thickness 70202 such thatit is predominantly stiff or rigid, even when placed under tensionagainst a rounded surface. In another embodiment, platform 70240 may bemore flexible, to allow for greater bending around a surface. Usingvarious combinations of dimensions and materials, rongeur 70290 may beconfigured to cut any of a number of tissues in any of a number oflocations in the body.

Referring now to FIG. 239, another embodiment of an articulating rongeur70310 is shown in cross-section. Articulating rongeur 70310 (of whichonly a portion is shown) may include a shaft 70311 having a proximalshaft portion 70312, a distal shaft platform 70314 (or “substrate” or“extension”), and an articulation feature 70316. Shaft 70311 may alsoinclude an additional articulation feature 70318 and a distal tip 70315.Rongeur 70310 may also include a proximal blade 70322, slidably disposedon platform 70314 and coupled with a blade actuating wire 70326 thatextends through proximal shaft portion 70312 and out an aperturetherein. A distal blade 70324 may be fixedly attached to platform 70314,and a tissue capture member 70325 may be disposed between distal blade70324 and platform 70314 to capture cut tissue that passes under blade70324. Rongeur 70310 may further include one or more compression members70320, as described above in reference to FIGS. 237A and 237B.Compressive force may be applied to compression member 70320(hollow-tipped arrow) to articulate rongeur 70310 about articulationfeature 70316, and blade articulating wire 70326 may be advanced toadvance proximal blade 70322 (solid-tipped arrows) to cut tissue.

In the embodiment of FIG. 239, compression member 70320 extends throughproximal shaft portion 70312, through distal platform 70314, and intodistal tip 70315. When compressive force is applied to compressionmember 70320, the force is transmitted all the way to distal tip 70315,so that rongeur articulates both at articulation feature 70316 and atadditional articulation feature 70318. In some embodiments, it may bepossible to articulate rongeur incrementally, such as by articulating ina first increment at articulation feature 70316 and in a secondincrement at additional articulation feature 70318. It may also bepossible, in some embodiments, to apply sufficient compressive force tocompression member 70320 to bend or curl distal tip 70315, as shown inFIG. 239. Such bending may facilitate curving rongeur 70310 around acurve tissue surface, for example. As described above, in someembodiments, compressive force may also act to bend distal platform70314.

Referring now to FIG. 240, in one embodiment, an articulating tissuecutting device 70330 may suitably include a shaft 70331 having aproximal portion 70332, a distal portion 70334 including a distal tip70335, a first articulation feature 70336 and a second articulationfeature 70338. Device 70330 may further include a powered reciprocatingfile 70342 having multiple tissue cutting elements 70344 and coupledwith a drive mechanism 70346. A compressive member 70340 may be disposedthrough and attached to shaft 70331 for applying compressive force(hollow-tipped arrow) to articulate shaft 70331 at articulation features70336, 70338.

Shaft 70331 and compressive member 70340 may have any of the featuresdescribed above in relation to alternative embodiments. Poweredreciprocating file 70342 may comprise any suitable reciprocating filedevice, such as those known in the art and any reciprocating filesinvented in the future. Generally, file 70342 may be reciprocated backand forth (solid, double-headed arrows) by drive mechanism 70346 whiledevice 70330 is pulled back to urge cutting elements 70344 againsttarget tissue, so that cutting elements 70344 cut tissue. In someembodiments, cutting elements 70344 may open into a collection chamberor area in distal portion 70334, where cut tissue may be collectedand/or transported proximally through shaft 70331 and out of device70330.

In various embodiments, file 70342 and drive mechanism 70346 may takeany of a number of different forms. Various powered reciprocating filedevices are described, for example, in U.S. patent application Ser. No.11/406,486, titled “Powered Tissue Modification Devices and Methods,”and filed Apr. 17, 2006, now U.S. Pat. No. 7,938,830, the fulldisclosure of which is hereby incorporated by reference. In oneembodiment, reciprocating file 70342 may comprise a file such as thatinvented by Richard J. Harp, founder of SurgiFile, Inc. (The SurgiFiledevice is described, for example, in U.S. patent application Ser. No.11/259,625 (Pub. No. 2006/0161189), the full disclosure of which ishereby incorporated by reference). By including one or more articulationfeatures 70336, 70338 in shaft 70331, reciprocating surgical file device70330 may have enhanced ability to reach one or more difficult to reachanatomical areas and/or to gain leverage against one or more structuresto facilitate urging file 70342 against target tissue.

With reference now to FIG. 241, in one embodiment, an articulatingreciprocating file tissue cutting device 70350 may include a handle70352 with a power source connector 70354, a shaft 70356 having a firstarticulation feature 70358, a second articulation feature 70360 and adistal tip, and a reciprocating file 70364. The various portions ofshaft 70356 may have any of the features described above in relation tovarious alternative embodiments. An alternative embodiment of device70350 may include only one articulation feature 70358, 70360, ratherthan two. Otherwise, device 70350 may include any of the featuresdescribed in U.S. patent application Ser. No. 11/259,625 (Pub. No.2006/0161189), which was previously incorporated by reference.

FIG. 242 shows a distal portion of another alternative embodiment of anarticulating reciprocating file tissue cutting device 70370. In oneembodiment, device 70370 may include a handle connector 70372, a shaft70374 including a first articulation feature 70376, a secondarticulation feature 70378 and a distal tip 70380, and a reciprocatingfile 70382 having multiple tissue cutting elements 70384. As with theprevious embodiment, shaft 70374 may have any of the various featuresdescribed above in relation to other embodiments, and device 70370 mayhave any of the features described in U.S. patent application Ser. No.11/259,625 (Pub. No. 2006/0161189), which was previously incorporated byreference.

Referring now to FIG. 243, in another embodiment, an articulating tissuecutting device 70390 may include a shaft 70391 having a proximal portion70392, a distal portion 70394, a distal tip 70395, a first articulationfeature 70396 and a second articulation feature 70398. A compressionmember 70400 may be disposed through shaft 70391 to articulate shaft70391 at articulation features 70396, 70398. An electrosurgical tissuecutting member 70402 may extend through shaft 70391 and protrude through(or be exposed through) a window 70404 on distal portion 70394. Tissuecutting member 70402, for example, may comprise a radiofrequency (RF)device, such as a monopolar or bipolar electrosurgical device. In oneembodiment, tissue cutting member 70402 may be configured as a wireloop. Tissue cutting member 70402 may be advanced out of window 70404,activated with RF energy, and then retracted (hollow-tipped arrow) tocut tissue, such as ligamentum flavum tissue in the spine or other softtissue. Further details of such RF tissue cutting devices are providedin U.S. patent application Ser. No. 11/405,848 (Publication No.US-2012-0078253-A9), which was previously incorporated by reference. Inone embodiment, tissue cut by tissue cutting member 70402 may fall intoa tissue collection chamber or hollow area in shaft distal portion70394.

In other alternative embodiments of an articulating tissue cuttingdevice, any of a number of other tissue cutting mechanisms may be used.Exemplary embodiments described above include bladed cutters,reciprocating files, and RF wire cutters, but any other suitable tissuecutting member (or members) may be included in alternative embodiments.For example, tissue cutting members may include but are not limited toblades, abrasive surfaces, files, rasps, saws, planes, electrosurgicaldevices, bipolar electrodes, monopolar electrodes, thermal electrodes,cold ablation devices, rotary powered mechanical shavers, reciprocatingpowered mechanical shavers, powered mechanical burrs, lasers, ultrasounddevices, cryogenic devices, and/or water jet devices.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. These and many other modificationsmay be made to many of the described embodiments. Therefore, theforegoing description is provided primarily for exemplary purposes andshould not be interpreted to limit the scope of the invention as it isset forth in the claims.

Percutaneous Spinal Stenosis Treatment

The present invention relates generally to medical/surgical devices andmethods. More specifically, the present invention relates to devices andmethods for spinal stenosis treatment.

In recent years, less invasive (or “minimally invasive”) surgicaltechniques have become increasingly more popular, as physicians,patients and medical device innovators have sought to reduce the trauma,recovery time and side effects typically associated with conventionalsurgery. Developing less invasive surgical methods and devices, however,poses many challenges. For example, less invasive techniques typicallyinvolve working in a smaller operating field, working with smallerdevices, and trying to operate with reduced or even no directvisualization of the structures being treated. These challenges areoften compounded when target tissues of a given procedure reside veryclose to one or more vital, non-target tissues.

One area of surgery which would likely benefit from the development ofless invasive techniques is the treatment of spinal stenosis. Spinalstenosis occurs when nerve tissue and/or the blood vessels supplyingnerve tissue in the spine become impinged by one or more structurespressing against them, causing symptoms. The most common form of spinalstenosis occurs in the lower (or lumbar) spine and can cause severepain, numbness and/or loss of function in the lower back and/or one orboth lower limb.

FIG. 1 is a top view of a vertebra with the cauda equina (the bundle ofnerves that extends from the base of the spinal cord) shown in crosssection and two nerve roots branching from the cauda equina to exit thecentral spinal canal and extend through intervertebral foramina oneither side of the vertebra. Spinal stenosis can occur when the spinalcord, cauda equina and/or nerve root(s) are impinged by one or moretissues in the spine, such as buckled or thickened ligamentum flavum,hypertrophied facet joint (shown as superior articular processes shownin FIG. 1), osteophytes (or “bone spurs”) on vertebrae,spondylolisthesis (sliding of one vertebra relative to an adjacentvertebra), facet joint synovial cysts, and/or collapse, bulging orherniation of an intervertebral disc. Impingement of neural and/orneurovascular tissue in the spine by one or more of these tissues maycause pain, numbness and/or loss of strength or mobility in one or bothof a patient's lower limbs and/or of the patient's back.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% of adults aged 50 and older and is the most frequentreason cited for back surgery in patients aged 60 and older. Patientssuffering from spinal stenosis are typically first treated withconservative approaches such as exercise therapy, analgesics,anti-inflammatory medications, and epidural steroid injections. Whenthese conservative treatment options fail and symptoms are severe, as isfrequently the case, surgery may be required to remove impinging tissueand decompress the impinged nerve tissue.

Lumbar spinal stenosis surgery involves first making an incision in theback and stripping muscles and supporting structures away from the spineto expose the posterior aspect of the vertebral column. Thickenedligamentum flavum is then exposed by complete or partial removal of thebony arch (lamina) covering the back of the spinal canal (laminectomy orlaminotomy). In addition, the surgery often includes partial or completefacetectomy (removal of all or part of one or more facet joints), toremove impinging ligamentum flavum or bone tissue. Spinal stenosissurgery is performed under general anesthesia, and patients are usuallyadmitted to the hospital for five to seven days after surgery, with fullrecovery from surgery requiring between six weeks and three months. Manypatients need extended therapy at a rehabilitation facility to regainenough mobility to live independently.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the effected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. Unfortunately, a surgical spine fusion results in a loss ofability to move the fused section of the back, diminishing the patient'srange of motion and causing stress on the discs and facet joints ofadjacent vertebral segments. Such stress on adjacent vertebrae oftenleads to further dysfunction of the spine, back pain, lower leg weaknessor pain, and/or other symptoms. Furthermore, using current surgicaltechniques, gaining sufficient access to the spine to perform alaminectomy, facetectomy and spinal fusion requires dissecting through awide incision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Thus, while laminectomy, facetectomy, and spinal fusion frequentlyimprove symptoms of neural and neurovascular impingement in the shortterm, these procedures are highly invasive, diminish spinal function,drastically disrupt normal anatomy, and increase long-term morbidityabove levels seen in untreated patients.

Therefore, it would be desirable to provide less invasive surgicalmethods and devices for treating spinal stenosis. For example, it wouldbe desirable to method and device for removing impinging tissue from aspine percutaneously, or at least with a minimally invasive incision,while maintaining safety and preventing damage to non-target tissues. Atleast some of these objectives will be met by the present invention.

Referring to FIGS. 244A-244D, one embodiment of a method for removingligamentum flavum (LF) tissue from a patient's spine is demonstrated. InFIGS. 244A-244D, a partial top view of a vertebra is shown, includingligamentum flavum (LF), facet joint (FJ), nerve root (NR) and caudaequina (CE). The patient's skin is also shown, although none of theanatomical structures, nor the various devices used therein, arenecessarily drawn to scale.

In one embodiment, referring to FIG. 244A, a tissue removal device 7510may be advanced percutaneously through a patient's skin to position adistal tip 7513 in the ligamentum flavum (LF) tissue. Device 7510 maycomprise a cannula (or “needle”) and in some embodiments may include anelongate shaft 7512 (including distal tip 7513), a first actuator 7514for extending a cutting member 7522 out of shaft 7512, and a secondactuator 7516 for moving cutting member 7522 along shaft 7512 to cuttissue. In some embodiments, cutting member 7522 may be coupled with anenergy source 7518 via one or more wires 7520 or other connectingmembers. For example, in one embodiment cutting member 7522 may comprisea radiofrequency (RF) cutting member, such as a bipolar or monopolarwire or wire loop, and power source 7518 may comprise any suitable RFgenerator. Alternative embodiments are described further below.

With distal tip 7513 located in ligamentum flavum tissue, and referringnow to FIG. 244B, cutting member 7522 may be extended out of a window oraperture on shaft 7512. In one embodiment, as shown, cutting member 7522may be extended out of shaft 7512 by advancing first actuator 7514 alongshaft 7512. In alternative embodiments, actuator 7514 may be moved oractuated in other ways to extend cutting member 7522. In otheralternative embodiments, cutting member 7522 may automatically extendout of a window or aperture of shaft 7512 when such a window or apertureis opened.

To confirm placement of distal tip 7513 in ligamentum flavum (LF), anysuitable technique may be used. For example, in some embodiments all orpart of shaft 7512 and distal tip 7513 may be radiopaque, and aphysician may view the location of shaft 7512 and distal tip 7513 viafluoroscopy. In some embodiments, cutting member 7522 may also serve asa nerve stimulation member. In such embodiments, when cutting member7522 is extended into tissue, it may be activated, such as bytransmitting RF energy, and the patient may be monitored for a responseto the stimulation. For example, if cutting member 7522 wereaccidentally placed into a nerve or nerve root, rather than ligamentumflavum (LF), activating cutting member 7522 with a stimulating currentwould typically cause a response in the nerve, seen as a muscle twitchand/or detectable using a monitoring technique, such as electromyography(EMG). If cutting member 7522 were in contact with a nerve, thephysician might withdraw cutting member 7522 and device 7510 andreposition distal tip 7513.

Once cutting member 7522 is extended into ligamentum flavum (LF) tissue,energy, such as RF energy, may be transmitted to cutting member 7522 viapower source 7518, and cutting member 7522 may be moved through thetissue (hollow-tipped arrow), such as by sliding second actuator 7516along shaft 7512. In some embodiments, as shown, cutting member 7522 maybe retracted, while in others it may be advanced, rotated, reciprocatedor moved in any of a number of suitable ways to cut tissue.

As seen in FIG. 244C, one or more pieces of cut tissue 7524 may becollected in shaft 7512. For example, in one embodiment, suction may beapplied at the proximal end of shaft 7512, causing cut tissue 7524 to besucked into the hollow inner lumen of shaft 7512. Alternatively, oradditionally, cutting member 7522 may have a configuration that directscut tissue into shaft 7512. In one embodiment, for example, cuttingmember 7522 may comprise an electrosurgical RF wire loop configured tocut one or more strips of tissue, which pass beneath the wire as theyare cut and pass into shaft 7512. Cut tissue 7524 may be removed fromthe patient by suctioning or otherwise pulling tissue 7524 through shaft7512 and out its proximal end, by removing device 7510 from the patientwith tissue 7524 contained in shaft 7512, or some combination thereof.

After ligamentum flavum (LF) tissue on one side of the vertebra isremoved, device 7510 may be repositioned to remove similar tissue on theopposite side. As shown in FIG. 244D, device 7510 may then be removed,leaving ligamentum flavum (LF) tissue reduced in size and no longerimpinging on cauda equina (CE) or nerve root (NR) tissue. FIGS.244A-244D demonstrate one embodiment of a method for removing tissuefrom a spine to treat spinal stenosis. A number of alternativeembodiments are described below.

Referring now to FIGS. 245A and 245B, top and side/cross-sectionalviews, respectively, of one embodiment of a percutaneous tissue removaldevice 7530 are shown. In this embodiment, device 7530 may include acannula/needle shaft 7532 having a window 7536 and a distal tip 7534, afirst actuator 7533 for retracting a cover 7538 over window 7536, asecond actuator 7535 for retracting and advancing a cutting member 7531to cut tissue, and a return electrode 7531′.

As best seen in FIG. 245B, cover 7538 may comprise, in some embodiments,an inner shaft slidably disposed within the outer shaft 7532. Inembodiments using RF or other energy modalities, all or part of shaft7532 and/or cover 7538 may be made of, coated with, covered with, mixedwith or otherwise coupled with one or more insulating materials, toprevent damage to non-target tissues from heat, electricity or the like.Any suitable biocompatible insulating materials, either now known orhereafter invented or discovered may be used. In various embodiments,shaft 7532 and cover 7538 may have any suitable dimensions and may bemade of any suitable materials. For example, in various embodiments,shaft 7532 and cover 7538 may be made from any of a number of metals,polymers, ceramics, or composites thereof. Suitable metals, for example,may include but are not limited to stainless steel (303, 304, 316,316L), nickel-titanium alloy, tungsten carbide alloy, or cobalt-chromiumalloy, for example, Elgiloy® (Elgin Specialty Metals, Elgin, Ill., USA),Conichrome® (Carpenter Technology, Reading, Pa., USA), or Phynox® (ImphySA, Paris, France). Suitable polymers include but are not limited tonylon, polyester, Dacron®, polyethylene, acetal, Delrin® (DuPont,Wilmington, Del.), polycarbonate, nylon, polyetheretherketone (PEEK),and polyetherketoneketone (PEKK). In some embodiments, polymers may beglass-filled to add strength and stiffness. Ceramics may include but arenot limited to aluminas, zirconias, and carbides. While device 7530 ofFIGS. 245A and 245B is shown having a rigid cannula shaft 7532, inalternative embodiments, shaft 7532 may be partially flexible and/or mayhave one or more articulating portions. Such alternative embodiments aredescribed further below.

Cutting member 7531 may comprise a wire loop RF electrode of ashape-memory or super-elastic material, such that when cover 7538 isretracted to open window 7536, the looped portion of cutting member 7531automatically extends out of window 7536. Cutting member 7531 may thenbe retracted, using second actuator 7535, to cut tissue. Cutting member7531 may extend through shaft 7532 (dotted lines) and exit proximally,for connection to an external power source (not shown), which maycomprise any suitable RF source or other power source in alternativeembodiments. In some embodiments, cutting member 7531 and returnelectrode 7531′ may form a bipolar electrosurgical cutting device, suchthat RF energy transmitted from a power source through cutting member7531 and thus through tissue is returned through device 7530 via returnelectrode 7531′. In an alternative embodiment, cutting member 7531 maycomprise a monopolar electrosurgical device, in which case a returnelectrode may be placed separately on a patient. Due to the proximity ofnervous tissues, it may be advantageous to use bipolar electrosurgicaldevices in spinal procedures, although it may also be possible to usemonopolar devices.

In an alternative embodiment, window 7536 may be replaced with one ormore small apertures, and first actuator 7533 may be configured toextend cutting member 7531 out of shaft 7532 through such apertures andretract cutting member 7531 back into shaft 7532 after use. In such anembodiment, second actuator 7535 may be used to move cutting member 7531back and forth longitudinally, relative to shaft 7532, to cause cuttingmember 7531 to cut tissue. In another alternative embodiment, cuttingmember 7531 may be advanced out of one or more apertures on shaft 7532,and shaft 7532 may be retracted and/or advanced to move cutting member7531 through tissue and thus cut the tissue.

Cutting member 7531 may comprise any suitable RF electrode, such asthose commonly used and known in the electrosurgical arts. Any of anumber of different ranges of radio frequency may be applied to cuttingmember 7531, according to various embodiments. For example, someembodiments may use RF energy in a range of between about 70 hertz andabout 5 megahertz. In some embodiments, the power range for RF energymay be between about 0.5 Watts and about 200 Watts. Additionally, invarious embodiments, RF current may be delivered directly intoconductive tissue or may be delivered to a conductive medium, such assaline or Lactate Ringers solution, which may in some embodiments beheated or vaporized or converted to plasma that in turn modifies targettissue. Similarly, cutting member 7531 may be powered by an internal orexternal RF generator. Any suitable generators may be used, such asthose commonly available at the present time and any generators inventedhereafter. Examples of external generators that may be used include, butare not limited to, those provided by ValleyLabs (a division of TycoHealthcare Group, LP (Pembroke, Bermuda and Princeton, N.J.)), GyrusMedical, Inc. (Maple Grove, Minn.), and the high-frequency generatorsprovided by Ellman International, Inc. (Oceanside, N.Y.).

In various embodiments, many of which are described in further detailbelow, cutting member 7531 may comprise one or more devices and may haveany of a number of configurations, sizes, shapes and the like. In otherwords, although energy such as RF energy may be applied to a bipolarloop electrode cutting member 7531, as shown in FIGS. 245 and 246, inalternative embodiments RF or other energy may be applied to any of anumber of alternative tissue cutting devices. Examples of such cuttingdevices include, but are not limited to, blades, abrasive surfaces,files, rasps, saws, planes, electrosurgical devices, bipolar electrodes,monopolar electrodes, thermal electrodes, cold ablation devices, rotarypowered mechanical shavers, reciprocating powered mechanical shavers,powered mechanical burrs, lasers, ultrasound devices, cryogenic devices,and water jet devices. Some embodiments may include an energytransmission member to cut tissue, while others may include a poweredmechanical tissue cutter, a manual mechanical cutter, or somecombination of energy transmitting, powered and/or mechanical cutters.For example, some embodiments may include one or more sharp bladescoupled with an RF power source.

Referring now to FIGS. 246A-246E, a distal portion of percutaneoustissue removal device 7530 is shown in greater detail. In FIG. 246A, thedistal portion of device 7530 is positioned in ligamentum flavum tissue7533, and cover 7538 is in an advanced position, covering window 7536.Window 7536 may be covered, for example, as device 7530 is passed intotissue. Cutting member 7531 may be disposed in shaft 7532 such that itis restrained by cover 7538. In some embodiments, cutting member 7531may comprise a bipolar wire loop electrode, with only a distal loopportion of the wire exposed and with the proximal portions of the wirecovered with insulating shafts 7535 (not shown in FIGS. 245A and 245B),which may act to insulate the proximal portions of cutting member 7531and may also facilitate advancing and retracting cutting member 7531relative to shaft 7532. In an alternative embodiment (e.g., FIG. 254D),cutting member may pass through one or more tracks or tubes coupled withan inner wall of shaft 7532. An inner wall of cover 7538 and/or shaft7532 may form a central lumen 7539 of device 7530, in which cut tissuemay be collected and/or through which cut tissue may be removed.

Once the distal portion of device 7530 is positioned in ligamentumflavum tissue 7533, which may be confirmed, for example, by fluoroscopy,cover 7538 may be retracted to open window 7536, as in FIG. 246B. Insome embodiments, when cover 7538 is retracted, wire loop cutting member7531 may automatically extend through window 7536 to contact tissue7533. In some embodiments, a stimulating current may then be passedthrough cutting member 7531, and the patient may be monitored for nerveresponse, to ensure that cutting member 7531 is not in contact withnerve tissue.

Cutting member 7531 may then be activated, with current returningproximally through return electrode 7531′. (In an alternativeembodiment, cutting member 7531 may be activated while window 7536 isclosed by cover 7538, so that cutting member 7531 is activated before itcontacts tissue 7533.) As in FIG. 246C, activated cutting member 7531may then be retracted to cut tissue 7533. Cut tissue 7533′ may then passinto lumen 7539. In some embodiments, cutting member 7531 may be shapedto urge cut tissue 7533′ into lumen 7539. Alternatively, oradditionally, suction may be applied to lumen 7539 to pull in cut tissue7533′.

In some embodiments, with one or more pieces of cut tissue 7533′ inlumen 7539, cover 7538 may be advanced to close window 7536, as in FIG.246D. At this point, suction may be applied to lumen 7539 (or continued,if already applied), to suck cut tissue 7533′ through lumen 7539 and outof the patient. In an alternative embodiment, cutting member 7531 may beused to pull cut tissue 7533′ through lumen. In another alternativeembodiment, a separate tissue engaging member may coupled with cuttissue 7533′ and be retracted to pull tissue 7533′ through lumen 7539.In yet another embodiment, device 7530 may be removed from the patientwith cut tissue 7533′ trapped in lumen 7539, cut tissue 7533′ may beremoved, and device 7530 may optionally be reinserted into the patientto remove more tissue 7533. In various embodiments, combinations ofthese methods for removing cut tissue 7533′ from the patient may beused.

As shown in FIG. 246E, after cutting tissue 7533, tissue cutting member7531 and cover 7538 may be returned to their original positions.Optionally, device 7530 may then be used to cut additional tissue 7533.

Referring now to FIGS. 247A-247E, in an alternative embodiment, apercutaneous tissue removal device 7540 may include an outer shaft 7542having a distal tip 7544 and a window 7546, an inner shaft 7547 slidablydisposed in outer shaft 7542 to act as a cover for window 7546, and ablade shaft 7548 slidably disposed in inner shaft 7547 and including apop-up blade 7549 with a sharp blade edge 7545. Outer shaft 7542, innershaft 7547, blade shaft 7548 and blade 7549 may be made of any suitablematerials, such as but not limited to the various metals, polymers,ceramics and composites listed above.

As shown in FIG. 247A, a distal portion of device 7540 may be insertedinto ligamentum flavum tissue 7543, with inner shaft 7547 advanced toclose window 7546 and to hold down blade 7549. Inner shaft 7547 may beretracted, as in FIG. 247B, to open window 7546 and allow blade 7549 topop up, thus exposing blade edge 7545 to tissue 7543. In one embodiment,blade 7549 may form a channel 7550 below it when it pops up, thuscreating a space through which cut tissue may pass into device 7540.

As shown in FIG. 247C, once blade shaft 7548 pops up into tissue, it maybe retracted to cut tissue 7543′, which passes through channel 7550 intodevice 7540. As shown in FIG. 247D, blade shaft 7548 may then beadvanced over cut tissue 7543′, and cut tissue 7543′ may be removedthrough lumen 7541. In various embodiments, cut tissue 7543′ may beremoved from a patient by suctioning the tissue through lumen 7541, bypulling the tissue through lumen 7541 using a tissue engaging device, orby removing device 7540 from the patient. As shown in FIG. 247E, bladeshaft 7548 may be retracted again, and may be advanced and retracted asmany times as desired, to cause blade 7549 to cut additional tissue7543″.

Referring to FIGS. 247F and 247G, more detailed side and bottom views,respectively, blade shaft 7548 and blade 7549 are provided. As seen inFIG. 247F, blade shaft 7548 may comprise a hollow shaft, forming lumen7541. Pop-up blade 7549 has cutting edge and forms channel 7550 belowit. In some embodiments, blade 7549 may be made of a shape-memory orsuper-elastic material, which is compressible within inner shaft 7547and resumes its popped-up or “proud” configuration when released fromconstraint. FIG. 247G is a bottom view of blade shaft 7548 and channel7550, from the perspective of the line A in FIG. 247F.

In alternative embodiments, a blade may be advanced rather thanretracted, two blades may be moved toward one another, or otherconfigurations of blades may be used. In some embodiments, energy (suchas RF energy) may be transmitted to blade 7549, to enhance tissuecutting. A number of different embodiments of bladed tissue cuttingdevices, any of which may be used percutaneously in various embodimentsof the present invention, are described in U.S. patent application Ser.No. 11/405,848, entitled “Mechanical Tissue Modification Devices andMethods,” and filed on Apr. 17, 2006, now Publication No.US-2012-0078253-A9, the full disclosure of which is hereby incorporatedby reference.

Referring now to FIGS. 248A-248E, in another alternative embodiment, apercutaneous tissue removal device 7552 may include an outer shaft 7554forming a window 7558, an inner shaft 7560, a tissue engaging member7556 having multiple barbs 7562, a first electrode 7568 coupled with alower surface of shaft 7554, and a second electrode 7569 coupled with anupper surface of shaft 7554 (“upper side” being defined as the same sidethat window 7558 opens on). Device 7552 is similar to that described inU.S. patent application Ser. No. 11/193,581, by Solsberg et al.,entitled “Spinal Ligament Modification,” now U.S. Pat. No. 7,896,879,the full disclosure of which is hereby incorporated by reference. Device7552, however, includes additional features not described in theforegoing reference.

During percutaneous insertion of device 7552 into ligamentum flavumtissue 7566, inner shaft 7560 may be in an advanced position to closewindow 7558. In some embodiments, window 7558 may be visible underexternal imaging guidance, such as fluoroscopy, to facilitate orientingwindow 7558 away from the epidural space of the spine and thus protectnon-target structures from injury during the surgical procedure. Inother embodiments, an endoscopic visualization device may be coupledwith device 7552 to facilitate internal imaging. Examples of suchvisualization devices include, but are not limited to, flexible fiberoptic scopes, CCD (charge-coupled device) or CMOS (complementarymetal-oxide semiconductor) chips at the distal end of flexible probes,LED illumination, fibers or transmission of an external light source forillumination, and the like.

Once a distal portion of device 7552 is positioned in the ligamentumflavum or other tissue removal site, nerve stimulating energy may betransmitted through first electrode 7568 or second electrode 7569, andthe patient may be monitored for a nerve response. If a nerve responseis detected, it may be determined that device 7552 is too close tonervous tissue to safely perform a procedure, and device 7552 may berepositioned in tissue 7566. Optionally, the other electrode, which wasnot already activated, may be activated to see if it stimulates nervoustissue. Alternative embodiments may include only one electrode or morethan two electrodes. In any case, based on the stimulation or lack ofstimulation of nerve tissue by one or both electrodes 7568, 7569, it maybe determined that device 7552 is in a safe location for performing atissue removal procedure. Various methods and apparatus for stimulatingelectrodes and monitoring for response are described in U.S. patentapplication Ser. No. 11/429,377, entitled “Spinal Access and NeuralLocalization,” and filed Jul. 13, 2006, now U.S. Pat. No. 8,048,080, thefull disclosure of which is hereby incorporated by reference.

With the distal portion of device 7552 positioned in a desired locationin ligamentum flavum tissue 7566, inner shaft 7560 may be retracted/slidproximally so that it no longer closes window 7558, as shown in FIG.248B. If it was not already present in device 7552, tissue engagingmember 7556 may be inserted through inner shaft 7560 so that it contactsligamentum flavum tissue 7566 via window 7558. In various embodiments,tissue engaging member 7556 may comprise a needle, hook, blade, tooth orthe like, and may have at least one flexible barb 7562 or hook attachedto its shaft. In some embodiments, barbs 7562 may extend aroundapproximately 120 degrees of the circumference of the shaft. In someembodiments, barbs 7562 may be directed towards the proximal end of thetool, as in FIGS. 248A-248E. When tissue engaging member 7556 isretracted slightly, barbs 7562 engage a segment of tissue 7566.Depending on the configuration of barbs 7562, the tissue sample engagedby barbs 7562 may be generally cylindrical or approximatelyhemispherical.

Referring to FIG. 248C, once tissue engaging member 7556 has engaged thedesired tissue 7566, inner shaft 7560, which is preferably provided witha sharpened distal edge, is advanced so that it cuts the engaged tissuesection 7566′ or sample loose from the surrounding tissue 7566. Hence,inner shaft 7560 also functions as a cutting means in this embodiment.In alternative embodiments, a cylindrical outer cutting element may beextended over outer shaft 7552 to cut tissue 7566.

Referring to FIG. 248D, once tissue 7566′ has been cut, tissue engagingmember 7556 may be pulled back through inner shaft 7560 so that cuttissue segment 7566′ may be retrieved and removed from barbs 7562.Tissue engaging member 7556 may then be advanced, as in FIG. 248E, andthe process of engaging and cutting tissue may be repeated until adesired amount of ligamentum flavum tissue 7566 has be removed (e.g.,when a desired of amount of decompression has been achieved).

In various embodiments, device 7552 may have one or more additionalfeatures, some of which are described in greater detail below. Forexample, in some embodiments, the distal portion of device 7552 may bearticulatable relative to a proximal portion of device 7552, tofacilitate passage of the distal portion into or through curved passagesor channels, such as an intervertebral foramen. In another embodiment,the distal portion of device 7552 may be flexible and/or curved, againto facilitate passage at least partway into an intervertebral foramen.In either an articulatable or a flexible embodiment, device 7552 mayoptionally also include a guidewire coupling member for attaching device7552 with a guidewire. Such a guidewire may be used to pull device 7552into place and apply force to device 7552 to urge barbs 7562 into tissue7566. Examples of various guidewire mechanisms are described in greaterdetail in U.S. patent application Ser. Nos. 11/468,247 (now U.S. Pat.No. 7,857,813) and 11/468,252 (now Publication No. US-2008-0086034-A1),both of which are entitled “Tissue Access Guidewire System and Method,and both of which were filed on Aug. 29, 2006, the full disclosures ofwhich are hereby incorporated by reference. In an alternativeembodiment, device 7552 may include a guidewire lumen or track over sothat device 7552 may be passed into the spine over a guidewire. Some ofthese optional features are described in greater detail below.

Referring now to FIG. 249, in another alternative embodiment, apercutaneous tissue removal device 75130 may include a shaft 75132having a window 75134 therein, a cover 75136 or inner shaft slidablydisposed in shaft 75132 for opening and closing window 75134, and acylindrical, rotating blade 75138 having a sharpened blade edge 75139and a hollow central channel 75137. Device 75130 may be coupledproximally with a drive mechanism and power source (not shown) to driveblade 75138. As in previously described embodiments, cover 75136 mayretract to expose blade 75138. Blade 75138 may rotate (curved arrows) aswell as advance and retract (double, hollow-tipped arrow) to cut tissue,which may then pass through hollow channel 75137. In some embodiments,device 75130 may include or be couplable with a suction device to suckcut tissue through channel 75137. Blade 75138 may be made of metal orany other suitable material, such as polymers, ceramics, or compositesthereof. Suitable metals, for example, may include but are not limitedto stainless steel (303, 304, 316, 316L), nickel-titanium alloy,tungsten carbide alloy, or cobalt-chromium alloy, for example, Elgiloy®(Elgin Specialty Metals, Elgin, Ill., USA), Conichrome® (CarpenterTechnology, Reading, Pa., USA), or Phynox® (Imphy SA, Paris, France).Ceramics may include but are not limited to aluminas, zirconias, andcarbides.

Referring to FIG. 250, in one embodiment, a percutaneous tissue removaldevice 75140 may include a shaft 75142 having a window 75144 therein, acover 75146 or inner shaft slidably disposed in shaft 75142 and forminga lumen 75145, and a cylindrical, rotating blade 75148 having asharpened blade edge 75149 and coupled with a drive shaft 75147. Driveshaft 75147 may be coupled proximally with a drive mechanism and powersource (not shown) to drive blade 75148. Blade 75148 may rotate (curvedarrows) as well as advance and retract (double, hollow-tipped arrow) tocut tissue, which may then pass through blade 75148 and into lumen75145. In some embodiments, device 75140 may include or be couplablewith a suction device to suck cut tissue through lumen 75145. Blade75148 may be made of metal or any other suitable material, such aspolymers, ceramics, or composites thereof. Suitable metals, for example,may include but are not limited to stainless steel (303, 304, 316,316L), nickel-titanium alloy, tungsten carbide alloy, or cobalt-chromiumalloy, for example, Elgiloy® (Elgin Specialty Metals, Elgin, Ill., USA),Conichrome® (Carpenter Technology, Reading, Pa., USA), or Phynox® (ImphySA, Paris, France). Ceramics may include but are not limited toaluminas, zirconias, and carbides.

Referring now to FIGS. 251A and 251B, in one embodiment, a percutaneoustissue removal device 75150 may include a shaft 75152 having a window75154 therein forming a lumen 75155, and a reciprocating tissue cutter75158 having multiple tissue cutting elements 75159 and being attachedto a drive shaft 75157. Optionally, device 75150 may also include acover as described in various embodiments above but not shown in FIGS.251A and 251B. Drive shaft 75157 may be coupled proximally with a drivemechanism and power source (not shown) to drive reciprocating tissuecutter 75158. Tissue cutter 75158 may reciprocate (double, solid-tippedarrow) to cause cutting elements 75159 to cut tissue, which may thenpass through cutting elements 75159 and into lumen 75155. In someembodiments, device 75150 may include or be couplable with a suctiondevice to suck cut tissue through lumen 75155. Tissue cutter 75158 mayhave any suitable number, shape and size of cutting elements 75159, andboth cutter 75158 and elements 75159 may be made of metal or any othersuitable material, such as polymers, ceramics, or composites thereof.Suitable metals, for example, may include but are not limited tostainless steel (303, 304, 316, 316L), nickel-titanium alloy, tungstencarbide alloy, or cobalt-chromium alloy, for example, Elgiloy® (ElginSpecialty Metals, Elgin, Ill., USA), Conichrome® (Carpenter Technology,Reading, Pa., USA), or Phynox® (Imphy SA, Paris, France). Ceramics mayinclude but are not limited to aluminas, zirconias, and carbides.

Any of a number of suitable powered tissue removal devices may be usedpercutaneously to remove ligamentum flavum tissue and/or bone in thespine to treat neural impingement, neurovascular impingement and/orspinal stenosis. Examples of various alternative powered tissue removaldevices are provided in U.S. patent application Ser. No. 11/406,486,entitled “Powered Tissue Modification Devices and Methods,” and filedApr. 17, 2006, now U.S. Pat. No. 7,938,830, the full disclosure of whichis hereby incorporated by reference. Other powered devices which may beused percutaneously are described in U.S. patent application Ser. Nos.11/468,247 (now U.S. Pat. No. 7,857,813) and 11/468,252 (now PublicationNo. US2008-0086034-A1), both of which were previously incorporated byreference.

Referring now to FIG. 252, in one embodiment, a percutaneous tissueremoval device 7570 may include a cannula/needle shaft 7571 having arigid proximal portion 7572 and a flexible distal portion 7573. Device7570 may also include an energy transmitting cutting member 7582, afirst actuator 7574 for bending distal portion 7573, a second actuator7576 for moving cutting member 7582 along distal portion 7573, and apower source 7578 coupled with cutting member 7582 via wires 7580. Insome embodiments, distal portion 7573 may be sufficiently rigid topenetrate a patient's soft tissue and ligamentum flavum (LF) but alsosufficiently flexible to be able to bend or articulate relative toproximal portion 7572. In various embodiments, any of a number ofactuating/flexing/bending mechanisms may be incorporated in device 7570to allow distal portion 7573 to flex, such as pull wires, push wires orthe like. Examples and further description of articulating tissuecutting devices are provided, for example, in U.S. patent applicationSer. No. 11/538,345, entitled “Articulating Tissue Cutting Devices,” andfiled Oct. 3, 2006, now Publication No. US-2008-0161809-A1, the fulldisclosure of which is hereby incorporated by reference.

In various alternative embodiments, device 7570 may be percutaneouslyadvanced into a patient to advance distal portion 7573 in ligamentumflavum tissue, between ligamentum flavum tissue and bone, and betweenligamentum flavum tissue and nervous tissue. Flexible distal portion7573 may allow or facilitate passage of at least part of distal portion7573 into an intervertebral foramen (IF) of the spine. Cutting member7582 and the various other features of device 7570 may be similar to anyof those described in reference to alternative embodiments above.

Referring now to FIG. 253, in an alternative embodiment, a percutaneoustissue removal device 7590 may include a cannula/needle shaft 7591having a rigid proximal portion 7592, a rigid distal portion 7593 thatarticulates relative to proximal portion 7592, and a distal tip 7595that articulates relative to distal portion 7593. Device 7590 may alsoinclude an energy transmitting cutting member 75102, a first actuator7594 for articulating distal portion 7593 and distal tip 7595, a secondactuator 7596 for moving cutting member 75102 along distal portion 7593,and a power source 7598 coupled with cutting member 75102 via wires75100. As with the previously described embodiment, any of a number ofactuating mechanisms may be incorporated in device 7590 for actuation ofdistal portion 7593 and distal tip 7595, such as but not limited tothose described in U.S. patent application Ser. No. 11/538,345, nowPublication No. US-2008-0161809-A1, which was previously incorporated byreference. Cutting member 75102 and the various other features of device7590 may be similar to any of those described in reference toalternative embodiments above.

Referring now to FIG. 254A, another embodiment of a percutaneous tissueremoval device 75110 is shown in place for performing a procedure in apatient. In one embodiment, tissue removal device 75110 may include ashaft 75111 having a rigid proximal portion 75112, a flexible distalportion 75113, an energy transmitting cutting member 75122, a handle75114 coupled with shaft proximal end 75112 for articulating and movingcutting member 75122 along distal portion 75113, and a power source75116 coupled with cutting member 75122 via wires 75118. Additionally,device 75110 may include a guidewire 75120, which is couplable withdistal portion 75113, and a guidewire handle 75124 removably couplablewith guidewire 75120. Guidewire 75120 and guidewire handle 75124 may beused to pull distal portion 75113 into a desired location in thepatient. Such a method and system are described in greater detail inU.S. patent application Ser. Nos. 11/468,247 (now U.S. Pat. No.7,857,813) and 11/468,252 (now Publication No. US-2008-0086034-A1),which were previously incorporated by reference.

As seen in FIGS. 254B and 254C, distal shaft portion 75113 may include awindow 75115, through which a wire loop electrode cutting member 75122may extend or simply be exposed. Distal portion 75113 may also include aguidewire coupling member 75117 at or near its extreme distal end.Again, for further details regarding various guidewire coupling members75117 and corresponding guidewires, reference may be made to U.S. patentapplication Ser. Nos. 11/468,247 (now U.S. Pat. No. 7,857,813) and11/468,252.

FIG. 254D shows the mechanism of cutting member 75122 in greater detail.A similar mechanism is described in U.S. patent application Ser. No.11/375,265, entitled “Methods and Apparatus for Tissue Modification,”and filed Mar. 13, 2006, now U.S. Pat. No. 7,887,538 the full disclosureof which is hereby incorporated by reference. Wire loop electrodecutting member 75122 may comprise any suitable RF electrode, such asthose commonly used and known in the electrosurgical arts, and may bepowered by an internal or external RF generator, such as the RFgenerators provided by ValleyLabs (a division of Tyco Healthcare Group,LP (Pembroke, Bermuda and Princeton, N.J.)), Gyrus Medical, Inc. (MapleGrove, Minn.), and the high-frequency generators provided by EllmanInternational, Inc. (Oceanside, N.Y.). Any of a number of differentranges of radio frequency may be used, according to various embodiments.For example, some embodiments may use RF energy in a range of betweenabout 70 hertz and about 5 megahertz. In some embodiments, the powerrange for RF energy may be between about 0.5 Watts and about 200 Watts.Additionally, in various embodiments, RF current may be delivereddirectly into conductive tissue or may be delivered to a conductivemedium, such as saline or Lactate Ringers solution, which may in someembodiments be heated or vaporized or converted to plasma that in turnmodifies target tissue.

In some embodiments, cutting member 75122 may be caused to extend out ofwindow 75115, expand, retract, translate and/or the like. Someembodiments may optionally include a second actuator (not shown), suchas a foot switch for activating an RF generator to delivery RF currentto an electrode.

Insulators 75126 may be disposed around a portion of wire loop cuttingmember 75122 so that only a desired portion of cutting member 75122 maytransfer RF current into target tissue. Cutting member 75122, coveredwith insulators 75126 may extend proximally into support tubes 75124. Invarious alternative embodiments, cutting member 75122 may be bipolar ormonopolar. For example, as shown in FIG. 254D, a sleeve 75128 housedtoward the distal portion of window 75115 may act as a return electrodefor cutting member 75122 in a bipolar device. Cutting member 75122 maybe made from various conductive metals such as stainless steel alloys,nickel titanium alloys, titanium alloys, tungsten alloys and the like.Insulators 75126 may be made from a thermally and electrically stablepolymer, such as polyimide, polyetheretherketone (PEEK),polytetrafluoroethylene (PTFE), polyamide-imide, or the like, and mayoptionally be fiber reinforced or contain a braid for additionalstiffness and strength. In alternative embodiments, insulators 75126 maybe composed of a ceramic-based material. Distal shaft portion 75113 mayalso be made of or coated or covered with one or more insulatingmaterials, such as those just listed.

In one embodiment, cutting member 75122 may be housed within distalportion 75113 during delivery of distal portion 75113 into a patient,and then caused to extend up out of window 75115, relative to the restof distal portion 75113, to remove tissue. Cutting member 75122 may alsobe flexible so that it may pop or bow up out of window 75115 and maydeflect when it encounters hard tissue surfaces. Cutting member 75122may have any of a number of shapes, such as curved, flat, spiral orridged. Cutting member 75122 may have a diameter similar to the width ofdistal portion 75113, while in alternative embodiments it may expandwhen extended out of window 75115 to have a smaller or larger diameterthan that of distal portion 75113. Pull wires (not shown) may beretracted proximally, in a manner similar to that described above, inorder to collapse cutting member 75122, decrease the diameter and lowerthe profile of the cutting member 75122, and/or pull cutting member75122 proximally to remove tissue or be housed within distal portion75113. The low profile of the collapsed cutting member 75122 facilitatesinsertion and removal of distal portion 75113 into and out of a patientprior to and after tissue modification. As the cutting member 75122diameter is reduced, support tubes 75124 deflect toward the center ofdistal portion 75113.

In an alternative embodiment (not shown), tissue modification device75110 may include multiple RF wire loops or other RF members. In anotherembodiment, device 75110 may include one or more blades as well as an RFwire loop. In such an embodiment, the wire loop may be used to remove orotherwise modify soft tissues, such as ligamentum flavum, or to providehemostasis, and blades may be used to modify hard tissues, such as bone.In other embodiments, as described further below, two separate tissuemodification devices 75110 (or more than two devices) may be used in oneprocedure to modify different types of tissue, enhance modification ofone type of tissue or the like.

In other alternative embodiments, tissue modification devices 75110 mayinclude tissue modifying members such as a rongeur, a curette, ascalpel, a scissors, a forceps, a probe, a rasp, a file, an abrasiveelement, one or more small planes, a rotary powered mechanical shaver, areciprocating powered mechanical shaver, a powered mechanical burr, alaser, an ultrasound crystal a cryogenic probe, a pressurized water jet,a drug dispensing element, a needle, a needle electrode, or somecombination thereof. In some embodiments, for example, it may beadvantageous to have one or more tissue modifying members that stabilizetarget tissue, such as by grasping the tissue or using tissue restraintssuch as barbs, hooks, compressive members or the like. In oneembodiment, soft tissue may be stabilized by applying a contained,low-temperature substance (for example, in the cryo-range oftemperatures) that hardens the tissue, thus facilitating resection ofthe tissue by a blade, rasp or other device. In another embodiment, oneor more stiffening substances or members may be applied to tissue, suchas bioabsorbable rods. In various embodiments, energy such as RF energymay be transmitted to any or all such tissue modification members, suchas an RF transmitting blade or the like.

Referring now to FIG. 13, in another embodiment a percutaneous tissueremoval device 75210 may comprise a multi-wire, partially flexiblerongeur-like device. Such devices are described in greater detail inU.S. patent application Ser. No. 11/535,000, titled “Tissue CuttingDevices and Methods,” and filed on Sep. 25, 2006, now Publication No.US-2008-0033465-A1, the full disclosure of which is hereby incorporatedby reference. In one embodiment, device 75210 may include a shaft 75211having a proximal portion 75212 and a distal portion 75213. In someembodiments, proximal shaft portion 75212 is predominantly rigid, and atleast part of distal shaft portion 75213 is flexible. Proximal shaftportion 75212 may be coupled with or may extend from a proximal handle75216. At least two flexible wires may slidably extend through a portionof proximal shaft portion 75212 and distal shaft portion 75213 so thattheir distal ends attach to a proximal blade 75226 and so that they canadvance proximal blade toward a distal blade 75226 to cut tissue betweenthem. A guidewire connector 75230 may be coupled with distal shaftportion 75213 anywhere along it length, such as at or near its extremedistal end. In some embodiments, tissue cutter device 75210 (or a systemincluding device 75210) may further include additional features, such asa guidewire 75232 with a sharp distal tip 75233 and configured to couplewith guidewire connector 75230, and a distal handle 75234 (or “guidewirehandle”) with a tightening lever 75236 for coupling with guidewire75232.

In some embodiments, tissue cutter device 75210 may be advancedpercutaneously into a patient's back by coupling guidewire connector75230 with guidewire 75232 that has been advanced between target andnon-target tissues, and then pulling guidewire 75232 to pull device75210 between the tissues. In alternative embodiments, device 75210 maybe advanced over guidewire 75232, such as via a guidewire lumen ortrack. The flexibility of distal shaft portion 75213 may facilitatepassage of device 75210 between tissues in hard-to-reach or tortuousareas of the body, such as between a nerve root (NR) and facet joint andthrough an intervertebral foramen (IF). Generally, device 75210 may beadvanced to a position such that blades 75226 face tissue to be cut in atissue removal procedure (“target tissue”) and one or more non-cuttingsurfaces of device 75210 face non-target tissue, such as nerve and/orneurovascular tissue. In the embodiment shown in FIG. 13, blades 75226are positioned to cut ligamentum flavum (LF) and may also cuthypertrophied bone of the facet joint, such as the superior articularprocess (SAP). (Other anatomical structures depicted in FIG. 13 includethe vertebra (V) and cauda equina (CE)).

Before or after tissue cutter device 75210 is pulled into the patient topull blades 75226 to a desired position, guidewire 75232 may beremovably coupled with distal handle 75234, such as by passing guidewire75232 through a central bore in handle 75234 and tightening handle 75234around guidewire 75232 via a tightening lever 75236. Proximal handle75216 and distal handle 75234 may then be pulled (hollow-tipped arrows)to apply tensioning force to device 75210 and thus to urge the cuttingportion of device 75210 (e.g., blades 75226) against ligamentum flavum(LF), superior articular process (SAP), and/or other tissue to be cut.Proximal handle 75216 may then be actuated, such as by squeezing in theembodiment shown, which advances the flexible wires and proximal blade75226, to cut tissue between blades 75226. Proximal handle 75216 may bereleased and squeezed as many times as desired to remove a desiredamount of tissue. When a desired amount of tissue has been cut,guidewire 75232 may be released from distal handle 75234, and cutterdevice 75210 and guidewire 75232 may be removed from the patient's back.

In various alternative embodiments of the method just described, device75210 may be positioned with at least part of distal shaft portion 75213located in ligamentum flavum tissue or above ligamentum flavum incontact with bone. In the latter example, device 75210 may be use to cutbone while leaving the ligamentum flavum largely or entirely intact.Again, for further description of various mechanical tissue modificationdevices, any of which may be used percutaneously, reference may be madeto U.S. patent application Ser. No. 11/535,000, now Publication No.US-2008-0033465-A1, which was previously incorporated by reference.

Referring now to FIG. 256, in some embodiments, a percutaneous tissueaccess device 75306 may be used to provide a safe conduit for insertingand using one or more tissue modification devices to treat spinalstenosis or neural/neurovascular impingement. Examples of access device75306 are described in greater detail in U.S. patent application Ser.Nos. 11/468,247 (now U.S. Pat. No. 7,857,813) and 11/468,252 (nowPublication No. US-2008-0086034-A1), which were previously incorporatedby reference. In some embodiments, tissue access device 75360 may bepercutaneously advanced to a position in a patient's back usingguidewire system 75240.

Tissue access device 75306 may include, for example, a proximal handle75307 having a hollow bore 75308 and an actuator 75309, a hollow shaft75310 extending from proximal handle 75307 and having a distal curvedportion and a distal window 75312, and a guidewire coupling member 75314coupled with a tapered distal end of shaft 75310. Any of a number ofdifferent tissue modification devices 75316, 75317, 75320 may beinserted and removed from access device 75306 to perform a tissuemodification procedure, such as a rongeur 75316, an ultrasound device75317 (including a wire 75318 and generator 75319), and an abrasivedevice 75320. Handle 75307 and actuator 75309 may be used to activateone or more tissue modifying members of various tissue modificationdevices. For example, rongeur 75316 may be advanced into hollow bore75308 and shaft 75310, to position blades 75321 of rongeur 75316 so asto be exposed through window 75312, and to lock a locking member 75315of rongeur 75316 within handle 75307. Actuator 75309 may then be movedback and forth (by squeezing and releasing, in the embodiment shown) tomove one or both blades 75321 back and forth to cut target tissue.Optionally, rongeur 75316 may then be removed from access device 75306and a different modification device 75317, 75320 inserted to furthermodify target tissue. Actuator 75309 may be used with some modificationdevices and not others. Again, in some embodiments, access device 75306,guidewire system 75240 and one or more modification devices 75316,75317, 75320 may be provided as a system or kit.

Referring now to FIGS. 257A-257E, in an alternative embodiment, a shieldor barrier 75500 (which may alternatively or additionally comprise atissue capture device) may be positioned between target and non-targettissue in a patient before the target tissue is modified. Such barriers75500 may be slidably coupled with, fixedly coupled with, or separatefrom the tissue modification devices with which they are used. Invarious embodiments, a barrier may be delivered between target andnon-target tissues before delivering the tissue modification device, maybe delivered along with the tissue modification device, or may bedelivered after delivery of the tissue modification device but beforethe device is activated or otherwise used to modify target tissue. Forexample, a barrier (or “shield”) may be coupled to the distal andproximal ends of a tissue modification device, specifically, it may becoupled to the distal and proximal ends of the tissue modificationregion (or distal flexible region) of a tissue modification device. Forexample, the device may slide over the distal tip of the device and thenclip onto a proximal portion of the device. The barrier may be made froma flexible and/or lubricious material, such as Teflon, for example. Inthis example, the barrier may be delivered along with the tissuemodification device. The barrier may be configured to reciprocate withthe tissue modification device or alternatively, the barrier may beconfigured to remain stationary as the tissue modification devicereciprocates over or above the barrier. In this variation, the barriermay be configured to couple to the tissue modification device such thatthe tissue modification device (or guidewire) may pull the barrier onlyin one direction. For example, the tissue modification device (orguidewire) may pull the barrier in a distal direction toward the desiredlocation within the spine (e.g. adjacent to non-target tissue) but willnot pull the barrier proximally and will allow the barrier to remain inplace will the device is pulled proximally.

In some embodiments, a first barrier may be removed from the device anda new or replacement barrier may be coupled to the device during use ofthe tissue modification device. For example, a user may remove tissuefrom a first portion of a spine while a first barrier is in place, thenthat first barrier may be removed and a second barrier may be coupled tothe device prior to removing tissue from a second portion of a spine.Alternatively, in some alternative embodiments, rather than, or inaddition to, coupling a barrier to a tissue modification device, alubricant, such as a sterile lubricant, may be applied to a portion ofthe tissue modification device, specifically for example, the portionthat may come into contact with non-target tissues. Generally, such abarrier or lubricant may be interposed between the non-target tissue andone or more tissue modification devices to prevent unwanted damage ofthe non-target tissue. Detailed description of various embodiments ofbarrier devices is provided in U.S. patent application Ser. No.11/405,859, titled “Tissue Modification Barrier Devices and Methods,”and filed Apr. 17, 2006, now Publication No. US-2007-0213734-A1, thefull disclosure of which is hereby incorporated by reference.

FIG. 257A shows a distal portion of an introducer device 75514 throughwhich barrier 75500 may be introduced. FIGS. 257B and 257C show oneembodiment of barrier 75500 partially deployed and in cross-section,respectively. Typically, barrier 75500 will have a first, small-profileconfiguration for delivery to an area near non-target tissue and asecond, expanded configuration for protecting the non target tissue. Invarious embodiments, barrier 75500 may have any of a number of sizes andshapes. For example, barrier 75500 is shown in FIG. 257B with a taperedend. In an alternative embodiment, barrier 75500 may instead have asquared-off end, a more rounded end, or the like.

In various embodiments, barrier 75500 may be configured as one piece ofsuper-elastic or shape-memory material, as a scaffold with materialdraped between the scaffolding, as a series of expandable wires ortubes, as a semicircular stent-like device, as one or more expandableballoons or bladders, as a fan or spring-loaded device, or as any of anumber of different devices configured to expand upon release fromdelivery device 75514 to protect tissue. As shown in FIGS. 257B and257C, barrier 75500 may comprise a sheet of material disposed with afirst end 75502 a abutting a second end 75502 b within introducer device75514 and unfurling upon delivery.

In an alternative embodiment, as shown in FIGS. 257D and 257E, oppositeends 75522 a and 75522 b of a barrier 75520 may overlap in introducerdevice 75514. Generally, barrier 75500, 75520 may be introduced viaintroducer device 75514 in one embodiment or, alternatively, may beintroduced via any of the various means described above for introducinga tissue modification device. In some embodiments, barrier 75500, 75520may be fixedly coupled with or an extension of a tissue modificationdevice. Barrier 75500, 75520 may also include one or more lumens, rails,passages, guidewire coupling members or the like for passing orconnecting with a guidewire or other guide member, for introducing,removing, steering, repositioning, or exchanging any of a variety oftissue modification, drug delivery, or diagnostic devices, for passing avisualization device, for passing a device designed for neurallocalization, for providing irrigation fluid and/or suction at thetissue modification site, and/or the like. In some embodiments, barrier75500, 75520 is advanced over multiple guidewires and the guidewiresremain in place during a tissue modification procedure to enhance thestability and/or maintain positioning of barrier 75500, 75520.

Introducer device 75514 may comprise any suitable catheter, introducer,sheath or other device for delivering one or more barrier devices into apatient. In various alternative embodiments, barrier devices may bedelivered into a patient either through a delivery device, over one ormore guide members, behind one or more guidewires, or some combinationthereof. In various embodiments, introducer device 75514 may have anysuitable dimensions, profile or configuration. For example, in variousembodiments, introducer device 75514 may have a circular cross-sectionalshape, an oval cross-sectional shape, or a shape that varies betweencircular and oval along the length of device 75514. In some embodiments,an outer diameter of introducer device 75514 or delivery device 75601may range from about 0.025″ to about 1.0″, with a wall thickness rangeof about 0.001″ to about 0.125″. Optionally, introducer device 75514 maytaper along its length. Introducer device 75514 may be rigid, partiallyflexible or flexible along its entire length and may be made from anysuitable material, such as but not limited to: a metal, such asstainless steel (303, 304, 316, 316L), nickel-titanium alloy,cobalt-chromium, or nickel-cobalt; a polymer, such as nylon, silicone,polyetheretherketone (PEEK), polyetherketoneketone (PEKK),polytetrafluoroethylene (PTFE), polyurethane (Tecothane), Pebax (co,USA), polycarbonate, Delrin (co, USA), high-density polyethylene (HDPE),low-density polyethylene (LDPE), HMWPE, and UHMWPE; or a combination ofmetals and polymers. Introducer device 75514 may be manufactured bymethods known in the art, such as CNC machining, extruding, casting,injection molding, welding, RF shaping, electrochemical fabrication(EFAB), LIGA (lithographic, galvanoforming and abforming), electricaldischarge machining (EDM) laser machining, silicon micromachining,weaving, braiding or non-woven fabrication techniques (e.g., spunbound,meltblown, and the like). In some embodiments, introducer device 75514may be woven from polymer or metal into a tube-like structure forflexibility and conformability. Such embodiments may optionally befiber-reinforced for added strength to allow for a thinner wallthickness.

FIGS. 258A and 258B illustrate how, in one embodiment, a barrier device751020 extending through a delivery device 75601 may help protect tissueduring a tissue modification procedure involving use of a tissuemodification device 751024. In various embodiments, tissue modificationdevice 751024 may include, but is not limited to, a rongeur, a curette,a scalpel, one or more cutting blades, a scissors, a forceps, a probe, arasp, a file, an abrasive element, one or more small planes, anelectrosurgical device, a bipolar electrode, a unipolar electrode, athermal electrode a rotary powered mechanical shaver, a reciprocatingpowered mechanical shaver, a powered mechanical burr, a laser, anultrasound crystal, a cryogenic probe, a pressurized water jet, or anycombination of such devices. Tissue modification device 751024 may beadvanced and retracted (double-headed arrows) freely on one side ofbarrier device 751020 and may be used to modify tissue, while barrierdevice 751020 protects non-target tissue from sustaining unwanteddamage. In some embodiments, barrier device 751020 may also be used tohelp guide tissue modification device 751024 to and/or from a positionfor performing a tissue modification procedure. Such guidance may beachieved by a shape, surface characteristic and/or one or more guidefeatures of barrier device 751020, according to various embodiments.

Turning to FIGS. 259A and 259B, in another embodiment, a barrier device751030 may include an open, shape-changing portion 751030, closed,elongate extensions 751034 extending from either end of shape-changingportion 751030, and at least one guide feature 751035 extending throughits length. Guide feature 751035 may include, in various embodiments,one or more guidewires (as shown), rails, impressions, lumens, tracks orthe like, any of which may facilitate guidance of a tissue modificationdevice 751032 along and/or through barrier device 751030. In variousembodiments, guide feature 751035 may comprise a separate device, notattached to barrier member 751030, as in the guidewire of FIGS. 259A and259B. Alternatively, one or more guide features 751035 may be attachedto, or integral with, barrier member 751030.

FIG. 260 shows an embodiment of a barrier device 751050 including acentral rail 751052 guide member along which a tissue modificationdevice 751054 may be guided.

FIG. 261 shows an alternative embodiment of a barrier device 751060including a central rail 751062 guide member along which a wire loop RFtissue modification device 751064 may be guided. In some embodiments,barrier devices 751050, 751060 and tissue modification devices 751054,751064 may be advanced through a delivery device 75601, while otherembodiments may not employ such a delivery device 75601.

Referring to FIG. 262, in one embodiment, a barrier device 751070 mayinclude a central channel 751072, accessible by a slit 751076, andmultiple flex grooves 751074. Multiple flex grooves 751074 mayfacilitate collapsing of barrier device 751070.

In another embodiment, as in FIG. 263, a barrier device 751080 may havea smooth, non-grooved surface and a central channel 751082, accessibleby a slit 751086. Slit 751076, 751086 may facilitate coupling anddecoupling of a tissue modification device with barrier device 751070,751080. Again, for further detailed description of variousbarrier/shield devices, reference may be made to U.S. patent applicationSer. No. 11/405,859, now Publication No. US-2007-0213734-A1, which waspreviously incorporated by reference.

Referring now to FIG. 264, in another embodiment, a ligamentum flavumretracting device 75730 may be used to help retract ligamentum flavumtissue (LF) away from cauda equina (CE) and/or nerve root (NR) tissue toalleviate spinal stenosis and/or neural/neurovascular impingement in thecentral spinal canal and/or lateral recess. Such a device 75730 isdescribed, for example, in U.S. patent application Ser. No. 11/251,199,now U.S. Pat. No. 8,192,435, which was previously incorporated byreference. Device 75730 may serve to retract spinal tissue posteriorlyand prevent the posterior elements, particularly the ligamentum flavum(LF), from buckling anteriorly into the spinal canal or lateral recess.Device 75730 may include an anterior anchor 75736, which may be placedanterior to or within the ligamentum flavum (LF), a posterior anchor75734, which may be placed posteriorly in tissue, such as posterior to alamina (L) of a vertebra, and a body 75732 extending between anchors75734, 75736 to provide tension between anchors 75734, 75736 and thusretract ligamentum flavum (LF). In one embodiment, body 75732 mayinclude a ratcheting mechanism, such that as it is pulled back throughposterior anchor 75734 it increases tension between anchors 75734, 75736and locks tighter and tighter.

FIG. 265 illustrates a rivet-like tissue retractor device 75740, whichmay be placed percutaneously through a hole drilled through a vertebrallamina (L). Device 75740 may include an anterior anchor 75746 forplacement in or anterior to the ligamentum flavum (LF), a posterioranchor 75744 for placement posterior to the lamina (L), and a body 75742between the two. Either of the two devices 75730, 75740 just describedmay be positioned and deployed using any suitable percutaneoustechnique. For example, spinal endoscopy may be used to place eitherligamentum flavum retraction device 75730, 75740 and/or to confirmcorrect placement and efficacy of device 75730, 75740.

FIGS. 266A-266P demonstrate another embodiment of a method forpercutaneously accessing and modifying tissue in a spine to ameliorateneural and/or neurovascular impingement and/or spinal stenosis. FIG.266A illustrates that a percutaneous access element, such as an epiduralneedle 75864, may be advanced percutaneously into a patient to positiona sharp distal tip 75866 in the epidural space 75842 of the spine. Forexample, needle 75864 may be inserted at, or one level below, the spinalinterspace where tissue removal is desired. Needle 75864 may be insertedinto the epidural space 75842 midline, ipsilateral, or contralateral tothe area where the spinal canal, lateral recess and/or neuroforaminalstenosis or impingement is to be treated. In some embodiments,percutaneous access may be aided by external or internal visualizationtechniques, such as fluoroscopy, epidural endoscopy, combinationsthereof, or the like.

In various embodiments, needle 75864 may have multiple barrels orlumens. In one embodiment, for example, a first lumen may extend fartherthan a second lumen. In one embodiment, a first lumen and/or a secondlumen may terminate in open or closed configurations at needle tip75866.

As shown in FIG. 266B, in some embodiments, a catheter 75824 may bepassed through needle 75864 to position a distal portion of catheter75824 in the epidural space 75842. The distal end of catheter 75824 mayinclude a protective hood 75860 (or “cap”), which as shown in FIG. 266C,may be expanded or opened (solid-tipped arrows). As shown in FIG. 266D,with hood 75860 opened, catheter 75824 may be slidably retracted throughneedle 75864 until hood 75860 covers needle tip 75866 (solid-tippedarrows). With hood 75860 covering needle tip 75866, catheter 75824 maybe fixed to needle 75864, thus providing a blunted needle 75864.

Referring to FIG. 266E, needle 75864 may be advanced (solid-tippedarrow) until needle tip 75866 is in a lateral recess 75808, adjacent toa neural foramen 75810. Needle tip 75866 may be positioned adjacent thelateral recess 75808, for example, by using tactile feedback from needle75864, image guidance (e.g. fluoroscopy), or combinations thereof.

In some embodiments, as shown in FIG. 266F, a neuralstimulation/localization device 75914 may be coupled with catheter75824, needle 75864 and/or a device within catheter 75824 or needle75864, such as a tissue protection barrier (not shown). Neuralstimulation device 75914 may comprise any currently known or hereafterinvented nerve stimulation devices, may include one or more controls,and may be configured to selectively deliver and/or sense electricalcurrent. Nerve stimulation may be used to assess and/or confirm desiredplacement of catheter 75824 and/or needle 75864 relative to nerve andtarget tissue. In some embodiments, catheter 75824 or needle 75864 mayfurther include one or more visualization devices, such as fiber opticsor other devices listed above. In some embodiments, the visualizationdevice may be covered by a clear distal tip and may be deployed in theepidural space 75842 integral with, or separate from but within,catheter 75824 or needle 75464.

Referring now to FIG. 266G, in one embodiment, a tissue protectionbarrier 75828 may be passed through or with needle 75864 and/or catheter75824 (solid-tipped arrows). Tissue protection barrier 75828 maycomprise, for example, any of the barrier devices described above or inU.S. patent application Ser. No. 11/405,859, now Publication No.US-2007-0213734-A1, which was previously incorporated by reference.Tissue protection barrier may be deployed into the lateral recess 75808and/or the neural foramen 75810, between target tissue, such asligamentum flavum (LF) and non-target tissue, such as dura mater 75846and associated neural (e.g., spinal cord, nerve roots, dorsal rootganglion) and neurovascular structures. In some embodiments, tissueprotection barrier 75828 may expand upon deployment from needle 75864 toassume an atraumatic, expanded profile with rounded edges. In variousembodiments, tissue protection barrier 75828 may comprise a catheter,curved or straight needle, curved or straight shield, sheath, backstop,stent, net, screen, mesh or weave, panel, fan, coil, plate, balloon,accordioning panels, or combinations thereof. In some embodiments,tissue protection barrier 75828 may have a tapered configuration.

In some embodiments, tissue protection barrier 75828 may include a frontside 75856 (i.e., working side) and a back side 75928 (i.e., neuralprotection side). Front side 75856 may be electrically isolated fromback side 75928. Either or both of front side 75856 and back side 75928may have an electrically conductive surface, and neural stimulationdevice 75914 may be in electrical communication with either or both. Invarious embodiments, neural stimulation may be monitored via spinalsomatosensory-evoked potentials (SSEPs), motor-evoked potentials (MEPs),and/or by looking for visual signs of muscular contraction within theextremities. SSEP, SEP, MEP or electromyogram (EMG) feedback may bemonitored and/or recorded visually, and/or may be monitored audibly,potentially conveying quantitative feedback related to the volume orfrequency of the auditory signal (e.g. a quantitative auditoryfeedback). Intensity of signal or stimulation may be monitored and usedto localize the nerve during placement. Further explanation and detailsof various embodiments of nerve stimulation and localization methods anddevices for use in spinal access are provided in U.S. patent applicationSer. No. 11/429,377, titled “Spinal Access and Neural Localization,” andfiled Jul. 13, 2006, now U.S. Pat. No. 8,048,080, the full disclosure ofwhich is hereby incorporated by reference.

FIG. 266H shows tissue protection barrier 75828 in its expandedconfiguration (solid-tipped arrows). In one embodiment, a balloon (notshown) may be inflated within tissue protection barrier 75828 to causeit to expand. In some embodiments, tissue protection barrier 75828 maybe twisted with respect to itself, such as for positioning. Inalternative embodiments, an electrical current and/or heat may beapplied to the tissue protection barrier 75828, which may be made from ashape memory alloy and may thus expand upon heating. In anotherembodiment, a spring may be positioned inside tissue protection barrier75828 to provide expansion. In yet another embodiment, tissue protectionbarrier 75828 may comprise a spring, such as a self-expandable stent ormesh. The spring may be releasably fixed in a compressed state when thetissue protection barrier 75828 is in the contracted configuration. Whenreleased, the spring may expand tissue protection barrier 75828. In someembodiments, the spring may be released by a trigger mechanism. In someembodiments, expansion of tissue protection barrier 75828 may apply anon-damaging pressure to the nerve branches 75862. Tissue protectionbarrier 75828 may include a window 75836, which may be open in thecontracted and/or expanded configuration of tissue protection barrier75828.

Referring now to FIG. 266I, a tissue removal device 75800 may beslidably deployed along, through, around or over needle 75864 and/orcatheter 75824. Tissue removal device 75800 may be deployed betweenimpinging target tissue, such as ligamentum flavum, and tissueprotection barrier 75828. Tissue removal device 75800 may have a controlhandle extending from the proximal end of the needle 75864. Tissueremoval device 75800 may be exposed to the impinging tissue through thewindow 75836.

Tissue removal device 75800 may include an energy delivery system 751114configured to deliver RF or other energy to target tissue. Such energymay be used to ablate, vaporize, break up, combinations thereof, orotherwise change the modulus of the tissue. In various alternativeembodiments, tissue removal device 75800 may be configured to deliverelectrical, ultrasound, thermal, microwave, laser, cryo (i.e., removingthermal energy), or combinations thereof. In one embodiment, forexample, tissue removal device 75800 may include one or moreelectrosurgery elements. The electrosurgery elements may be configuredto remove and/or ablate tissue, achieve hemostasis, and/or provideneural localization in tissue adjacent to the electrosurgery elements.The electrosurgery elements may be either monopolar or bipolar RF insome embodiments. In various embodiments, the RF elements may beactivated with a thermal or substantially non-thermal waveform. In otherembodiments, tissue removal device 75800 may include one or more lasers,high-pressure fluid devices, thermal elements, radioactive elements,textile electric conductors, conductive wire loops and/or needlesconfigured to be used in tissue contact (e.g., needle ablation),springs, open and/or spring wire weaves, conductive polymers that canhave conductive metals chemically deposited thereon, or combinationsthereof.

In FIG. 266J, tissue removal device 75800 is shown with multiple energytransmitting needles 75844 deployed into target ligamentum flavum tissue(LF) for delivering energy. Delivered energy may alter the compression,denaturation, electrosurgical exposure, thermal remodeling (hot orcold), chemical alteration, epoxy or glues or hydrogels, and/or modulusof elasticity of the impinging tissue. For example, the modulus ofelasticity of soft impinging tissue may be increased, which may improvepurchase on the soft impinging tissue with the tissue removal device75800. Remodeling of the tissue during modulus alteration may alleviateimpingement and obviate or reduce a need for tissue removal. Tissueremoval device 75800 may be designed to automatically stimulate the siteof tissue removal, or have the neural stimulation and localizationdevice 751114 stimulate the site of tissue removal, before or duringtissue removal. Tissue removal device 75800 may be configured toautomatically stop tissue removal when nerve stimulation is sensed bythe front side 75856, and/or no nerve stimulation is sensed by the backside 75928.

FIG. 266K illustrates that tissue removal device 75800 may have one ormore non-powered mechanical tissue removal elements. The non-poweredmechanical tissue removal elements can be abrasives such as abrasivebelts or ribbons, cutting elements such as blades, knives, scissors orsaws, rongeurs, grinders, files, debriders, scrapers, graters, forks,picks, burrs, rasps, shavers, or combinations thereof.

An external activating force, for example as shown by arrow 75830(activating tissue removal) on a handle, can activate tissue removaldevice 75800. The mechanical tissue removal elements may be used incombination or not in combination with the energy delivery device. Themechanical tissue removal elements may be pushed into and/or drawnacross the impinging tissue to remove the tissue by cutting, shaving,slicing, scissoring, guillotining, scraping, tearing, abrading,debriding, poking, mutilating, or combinations thereof. The mechanicaltissue removal elements (e.g., blades) may be drawn across the impingingtissue in a single direction and/or can be reciprocated. The mechanicaltissue removal elements may be manually controlled and/orelectronically, pneumatically or hydraulically powered. The mechanicaltissue removal elements may be embedded with abrasives and/or haveabrasive coatings, such as a diamond or oxide coating. Further detailsof various mechanical tissue modification devices are set forth aboveand in the patent applications incorporated by reference herein.

FIG. 266L shows tissue removal device 75800 after the blade has beenpassed proximally to cut tissue. The blade may be passed as many timesas desired, and then tissue removal device 75800 may be removed throughneedle 75864, as shown in FIG. 266M.

FIG. 266N illustrates that the tissue protection barrier 75828 may betransformed into a contracted configuration (solid-tipped arrows). FIG.266O illustrates that needle tip 75866 may be translatably retracted, asshown by arrow, from the neural foramen 75810 and lateral recess 75808.FIG. 266P illustrates that needle 75864 may be translatably withdrawnfrom the spine 75810 and the skin 75870.

Referring now to FIGS. 267A-267C, one embodiment of a portion of abarrier 75828 and tissue modifying device 75800 is shown. Tissue removaldevice 75800 may include one or more needlettes 75968 and may beslidably disposed within barrier 75828. Needlettes 75968 may each have aneedlette tip 75974 and may be configured to slide out of needletteports 75972 on top surface 75856 of barrier 75828. In some embodiments,needlette tips 75974 may be covered, coated or otherwise have a surfaceand/or by completely made from an electrically conductive material, andneedlettes 75468 may be covered, coated or otherwise have a surface madefrom an electrically resistive or insulating material. Needlette tips75474 may be configured to deliver electrical, ultrasound, thermal,microwave, laser and/or cryogenic energy.

In one embodiment, tissue protection barrier 75528 may include multipleneedlette conduits 75970. Needlettes 75968 may be slidably attached toneedlette conduits 75970. In alternative embodiments, needlettes 75468may be either solid or hollow, and in the latter case needlettes 75968may optionally be used to deliver one or more drugs or other substancesto target tissue.

Referring now to FIG. 268A, in one embodiment, needlette tip 75974 maycomprise a scooped shape 75996, such as a grater or shredder. Scoop75996 may have a tissue entry port 751024. Scoop 75996 may be open andin fluid communication with a hollow needlette 75968. Scoop 75996 mayhave a leading edge 75962, for example partially or completely aroundthe perimeter of the tissue entry port 751024. Leading edge 75962 may besharpened and/or dulled. Leading edge 75962 may be beveled. Leading edge75962 may be electrically conductive. Leading edge 75962 may beconfigured to emit RF energy. Leading edge 75962 may be a wire.Needlette tip 75974 other than leading edge 75962 may be electricallyresistive.

In an alternative embodiment, shown in FIG. 268B, needlette tip 75974may include a tip hole 751020. Tip hole 751020 may have a sharpenedperimeter. Tip hole 751020 may act as a tissue entry port. Tip hole751050 may be in fluid communication with hollow needlette 75968.Further details of these and other embodiments of tissue removal deviceshaving needlettes and barriers having needlette ports may be found inU.S. patent application Ser. No. 11/251,199, now U.S. Pat. No.8,192,435, which was previously incorporated by reference.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. These and many other modificationsmay be made to many of the described embodiments. Therefore, theforegoing description is provided primarily for exemplary purposes andshould not be interpreted to limit the scope of the invention as it isset forth in the claims.

Devices and Methods for Measuring the Space Around a Nerve Root

The present invention relates generally to medical/surgical devices andmethods. More specifically, the present invention relates to devices andmethods for measuring the size of a compliant region adjacent to apatient's nerve root, such as the intervertebral foramina, centralcanal, and/or lateral recess in a spine.

In recent years, less invasive (or “minimally invasive”) surgicaltechniques have become increasingly more popular, as physicians,patients and medical device innovators have sought to reduce the trauma,recovery time and side effects typically associated with conventionalsurgery. Developing less invasive surgical methods and devices, however,poses many challenges. For example, less invasive techniques typicallyinvolve working in a smaller operating field, working with smallerdevices, and trying to operate with reduced or even no directvisualization of the structures being treated. These challenges areoften compounded when target tissues of a given procedure reside veryclose to one or more vital, non-target tissues.

One area of surgery which would likely benefit from the development ofless invasive techniques is the treatment of spinal stenosis. Spinalstenosis occurs when nerve tissue and/or the blood vessels supplyingnerve tissue in the spine become impinged by one or more structurespressing against them, causing symptoms. The most common form of spinalstenosis occurs in the lower (or lumbar) spine and can cause severepain, numbness and/or loss of function in the lower back and/or one orboth lower limbs.

FIG. 1 is a top view of a vertebra with the cauda equina (the bundle ofnerves that extends from the base of the spinal cord) shown in crosssection and two nerve roots branching from the cauda equina to exit thecentral spinal canal and extend through intervertebral foramina (or“neural foramina”—singular “foramen”) on either side of the vertebra.Spinal stenosis can occur when the spinal cord, cauda equina and/ornerve root(s) are impinged by one or more tissues in the spine, such asbuckled or thickened ligamentum flavum, hypertrophied facet joint (shownas superior articular processes in FIG. 1), osteophytes (or “bonespurs”) on vertebrae, spondylolisthesis (sliding of one vertebrarelative to an adjacent vertebra), facet joint synovial cysts, and/orcollapse, bulging or herniation of an intervertebral disc. Impingementof neural and/or neurovascular tissue in the spine by one or more ofthese tissues may cause pain, numbness and/or loss of strength ormobility in one or both of a patient's lower limbs and/or of thepatient's back.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% of adults aged 50 and older and is the most frequentreason cited for back surgery in patients aged 60 and older. Patientssuffering from spinal stenosis are typically first treated withconservative approaches such as exercise therapy, analgesics,anti-inflammatory medications, and epidural steroid injections. Whenthese conservative treatment options fail and symptoms are severe, as isfrequently the case, surgery may be required to remove impinging tissueand decompress the impinged nerve tissue.

Lumbar spinal stenosis surgery involves first making an incision in theback and stripping muscles and supporting structures away from the spineto expose the posterior aspect of the vertebral column. Thickenedligamentum flavum is then exposed by complete or partial removal of thebony arch (lamina) covering the back of the spinal canal (laminectomy orlaminotomy). In addition, the surgery often includes partial or completefacetectomy (removal of all or part of one or more facet joints), toremove impinging ligamentum flavum or bone tissue. Spinal stenosissurgery is performed under general anesthesia, and patients are usuallyadmitted to the hospital for five to seven days after surgery, with fullrecovery from surgery requiring between six weeks and three months. Manypatients need extended therapy at a rehabilitation facility to regainenough mobility to live independently.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the effected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. Unfortunately, a surgical spine fusion results in a loss ofability to move the fused section of the back, diminishing the patient'srange of motion and causing stress on the discs and facet joints ofadjacent vertebral segments. Such stress on adjacent vertebrae oftenleads to further dysfunction of the spine, back pain, lower leg weaknessor pain, and/or other symptoms. Furthermore, using current surgicaltechniques, gaining sufficient access to the spine to perform alaminectomy, facetectomy and spinal fusion requires dissecting through awide incision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Thus, while laminectomy, facetectomy, and spinal fusion frequentlyimprove symptoms of neural and neurovascular impingement in the shortterm, these procedures are highly invasive, diminish spinal function,drastically disrupt normal anatomy, and increase long-term morbidityabove levels seen in untreated patients.

A number of devices, systems and methods for less invasive treatment ofspinal stenosis have been described by the assignee of the presentinvention. For example, various embodiments of such devices, systems andmethods are described in U.S. patent application Ser. Nos.: 11/250,332,entitled “Devices and Methods for Selective Surgical Removal of Tissue,”and filed Oct. 15, 2005, now U.S. Pat. No. 7,738,968; 11/375,265,entitled “Method and Apparatus for Tissue Modification,” and filed Mar.13, 2006, now U.S. Pat. No. 7,887,538; and 11/535,000, entitled TissueCutting Devices and Methods,” and filed Sep. 25, 2006, now PublicationNo. US-2008-0033465-A1 all of which applications are hereby incorporatedfully by reference herein.

One challenge in treating spinal stenosis using minimally invasive toolsis discerning how much space exists in the intervertebral foramenthrough which a given impinged nerve runs. Ideally, a surgeon performinga minimally invasive tissue removal procedure in the spine would be ableto discern how impinged a given nerve is at the start of the procedure,to what extent the foramen is being cleared of tissue during theprocedure, and how much room the nerve has within the foramen after theprocedure is completed. At the least, a surgeon will typically want toknow when the nerve is no longer being impinged by tissue and, thus,that the procedure may be complete. Making this determination in aminimally invasive setting may be quite challenging, since directvisualization of a foramen is typically not possible and soft tissuessuch as ligamentum flavum and nerve tissue are difficult or impossibleto visualize with intraoperative fluoroscopy.

U.S. Pat. Nos. 7,166,081 and 7,172,562 describe a system of multiplerigid probes with different-sized tips for measuring an intervertebralforamen. Although such probes may work in some cases in a traditional,open surgical procedure, such rigid probes will generally not be usefulfor a minimally invasive or percutaneous procedure. U.S. Pat. No.6,102,930 describes a balloon-tipped catheter device for measuring anintervertebral foramen. Again, this device is not configured to work ina minimally invasive or percutaneous procedure. As stated in the '930patent, “A laminectomy or laminotomy is performed at the appropriatevertebral segment to allow for access to the spinal canal.” [col. 2,lines 33-35]

Therefore, it would be desirable to have devices and methods formeasuring an intervertebral foramen to facilitate determination of theprogress and completion of a spinal decompression procedure. Ideally,such devices and methods would work in a minimally invasive and evenpercutaneous access setting, without requiring large incisions,laminotomies, laminectomies, or direct visualization of the foramen. Atleast some of these objectives will be met by the present invention.

The present invention is directed primarily to medical/surgical devices,systems and methods for measuring the compliant region adjacent to anerve root before, during and/or after a spine tissue removal procedure(or “decompression procedure”) of a constricted region surrounding thenerve root (e.g., within an intervertebral foramina, spinal canal and/orlateral recess). The devices, methods and systems described herein maybe used with any appropriate spinal treatment, including those describedin: U.S. patent application Ser. No. 11/251,205, entitled “Devices andMethods for Tissue Access,” and filed Oct. 15, 2005; U.S. patentapplication Ser. No. 11/457,416, entitled “Spinal Access and NeuralLocalization,” and filed Jul. 13, 2006, now U.S. Pat. No. 7,578,819;U.S. patent application Ser. No. 11/468,247, entitled “Tissue AccessGuidewire System and Method,” and filed Aug. 29, 2006, now U.S. Pat. No.7,857,813; U.S. patent application Ser. No. 11/251,165, entitled“Devices and Methods for Tissue Modification,” and filed Oct. 15, 2005,now U.S. Pat. No. 7,553,307; U.S. patent application Ser. No.11/375,265, entitled “Methods and Apparatus for Tissue Modification,”and filed Mar. 13, 2006, now U.S. Pat. No. 7,887,538; U.S. patentapplication Ser. No. 11/535,000, entitled “Tissue Cutting Devices andMethods,” and filed Sep. 5, 2006, now Publication No.US-2008-0033465-A1; and U.S. patent application Ser. No. 11/687,558,entitled “Flexible Tissue Removal Devices and Methods,” and filed Mar.16, 2007, now U.S. Pat. No. 8,062,298, all of which applications arehereby incorporated by reference herein in their entirety.

FIG. 269 is a side view of a portion of a lumbar spine without nerveroot impingement, showing two adjacent vertebrae, an intervertebraldisk, and a nerve root exiting an intervertebral foramen. Visible inthis view are vertebral bodies 802, pedicles 804, a facet joint 805, anda nerve root 806 passing through an open intervertebral foramen 807.

FIG. 270 is a side view of the same portion of lumbar spine with nerveimpingement as in a case of lateral recess and foraminal spinalstenosis. In this figure, there is collapse of disc space and boneosteophytes 808 with facet hypertrophy (enlargement) causing severecompression of nerve root 806. Ligamentum flavum 809 may also buckle,collapse and/or hypertrophy, thus further impinging on nerve root 806.

Referring to FIG. 271, one embodiment of a tissue removal device 8010for performing a minimally invasive or percutaneous spinal decompressionprocedure is shown. Device 8010 may suitably include a proximal handle8020 coupled with a shaft 8012 having a proximal, rigid portion 8013 anda distal, flexible portion 8014 on which one or more tissue modifyingmembers 8016 may be disposed. A guidewire coupler 8018 may be formed in(or attached to) flexible portion 8014 at or near its distal end, forcoupling with a guidewire 8022, which in turn may be coupled with aguidewire handle 8024 (or “distal handle”), which may include atightening lever 8025 for tightening handle 8024 around guidewire 8022.

Device 8010 is shown percutaneously placed in position for performing atissue modification procedure in a patient's spine, with variousanatomical structures shown including a vertebra V, cauda equina CE,ligamentum flavum LF, nerve root NR, facet F, and intervertebral foramenIF. Various embodiments of device 8010 may be used in the spine toremove ligamentum flavum LF, facet bone F, bony growths, or somecombination thereof, to help decompress cauda equina CE and/or nerveroot NR tissue and thus help treat spinal stenosis and/or neural orneurovascular impingement. Although this use of device 8010 will not becontinuously repeated for every embodiment below, any of the describedembodiments may be used to remove ligamentum flavum alone, bone alone,or a combination of ligament and bone in the spine to treat neuralimpingement, neurovascular impingement and/or spinal stenosis.

In one embodiment of a method for modifying tissue using device 8010, adistal end of 8022 guidewire may be placed into the patient, along acurved path between target and non-target tissue, and out of thepatient. A distal portion of guidewire 8022 may then be coupled withguidewire handle 8024, such as by passing guidewire 8022 through acentral bore in handle 8024 and tightening handle 8024 around guidewire8022 via tightening lever 8025 or other tightening means. A proximal endof guidewire 8022 may then be coupled with coupling member 8018 and usedto pull distal shaft portion 8014 between target and non-target tissues.In some embodiments, device 8010 may be advanced into the patientpercutaneously, while in alternative embodiments, device 8010 may beadvanced through a small incision or larger incision. Once advanced intothe patient, flexible distal shaft portion 8014 may be advanced along acurved path between the target and non-target tissues, and in someinstances may be pulled at least partway into an intervertebral foramenIF of the spine.

Proximal handle 8020 and guidewire handle 8024 may be pulled (or“tensioned”—solid/single-tipped arrows) to urge tissue modifying members8016 against the target tissue (in this case, ligamentum flavum LF).Generally, tissue modifying members 8016 may be fixedly attached to (orformed in) one side or surface of distal portion 8014, while an oppositeside or portion of distal portion 8014 faces non-target tissue, such ascauda equina CE and/or nerve root NR. The opposite side of distalportion 8014 will generally be atraumatic and/or include an atraumaticcover, coating, shield, barrier, tissue capture member or the like. Withtensioning force applied to device 8010, handles 8020, 8024 may be usedto reciprocate device 8010 back and forth (solid/double-tipped arrows)to cause tissue modifying members 8016 to cut, remove, shred orotherwise modify the target tissue. In various embodiments, for example,target tissue may include only ligamentum flavum LF, only bone, or acombination of both.

Reciprocation and tensioning may be continued until a desired amount oftissue is removed. Removed target tissue, in some embodiments, may becollected, captured or trapped between tissue modifying members 8016and/or in one or more tissue capture members or chambers (not shown).When a desired amount of target tissue has been removed, which may bedetermined, for example, by tactile feedback provided to the surgeon bydevice 8010, by radiographic imaging, and/or by direct visualization(such as in an open surgical case), guidewire 8022 may be released fromdistal handle 8024, and device 8010 may be removed from the patient'sback. If desired, device 8010 may be passed into the patient's spineagain for additional tissue modification, and/or other devices may bepassed into the spine.

In general, all of the devices, systems and methods described herein maybe adapted for use with a guidewire and/or bimanual operation similar tothat described above. The intervertebral foramina region is extremelynarrow, and includes one or more nerves, such as the nerve root. Whenmaneuvering within the intervertebral foramen, it is extremely importantto avoid damage to the nerve root. The use of a guidewire and/orbimanual manipulation approach is one way to prevent damage to the nerveroot. A bimanual approach allows both proximal and distal manipulationof the device (e.g., measuring device) from outside of the patient. Thebimanual manipulation may be performed using a guidewire by coupling thedistal end of a device to the proximal end of the guidewire, andtensioning the guidewire distally. Bimanual manipulation may also allowthe device to navigate the foramen, which may be irregularly shaped andcurved. Measuring devices that are not sufficiently flexible (andparticularly devices having rigid or stiff distal regions) may notprovide accurate measurements.

Any of the devices and systems described herein may be adapted forbimanual manipulation. For example, the distal region of any of themeasurement devices described herein may be flexible or bendable. Soundsor sounding regions on these devices may be rigid or incompressible (toprovide accurate estimates of foramen size), however the sound may belocated on a flexible string, backbone, cannula, etc. In some variationsthe proximal region is less flexible (and may even be rigid) than thedistal region. The proximal region may also include a handle, asdescribed in greater detail below. In some variations, the distal end(or a region near the distal end) includes a coupling region that isconfigured to couplet to a guidewire, and particularly the proximal endof a guidewire. Exemplary couplers may also be found, for example, inU.S. patent application Ser. No. 12/127,535, filed May 27, 2008, andtitled “GUIDEWIRE EXCHANGE SYSTEMS TO TREAT SPINAL STENOSIS,” nowPublication No. US-2008-0275458-A1. In general, these couplers mayinclude a mating region for mating with a portion of the guidewire. Forexample, the mating region may be a channel or opening into which theproximal end of the guidewire may be seated. The channel may include alock or locking member configured to secure the guidewire to thecoupler. In one variation the coupler is a seat that includes channelwith a proximal opening. The window narrows distally. A guidewire mayinclude an enlarged proximal end (e.g., a ball or cylinder of largerdiameter attached to the proximal end) that can seat into the coupler bypassing through the proximal window and sliding distally until it issecured in the narrowing channel by friction between the walls of thechannel and the proximal end of the guidewire.

Any of the devices described herein may also be adapted to stimulate anerve root. Stimulation may be provided to orient or guide themeasurement device (e.g., to prevent damage to the nerve as the deviceis positioned). In some variations, the stimulation may be provided andcontrolled to determine the size of the foramen relative to themeasurement device. This is described in greater detail below.

Any of the devices described herein may also be used with avisualization technique such as fluoroscopy. For example, a fluoroscopemay be used to visualize the intervertebral foramen to help guide themeasuring device, or to provide visual output on the size. Thus, themeasurement devices described herein may be adapted to allow directvisualization. For example, the devices may include indicator regionsthat can be visualized (e.g., under fluoroscopy) or calibration regionshaving a known measurement providing calibration of the fluoroscopicimage. Other variations are described below.

Any of the devices described herein may also include a moldable orformable region which may be inserted into the intervertebral foramenregion (or lateral recess, or central canal) in order to make a partialor complete mold of the space which can be withdrawn and examined. Forexample, a distal portion of the measurement device maybe moldable(e.g., made of a pliable or formable material).

Described below are variations of measuring devices for measuring thecompliant region adjacent to a nerve root, when the nerve root issurrounded by bone or other hard tissue that may impinge on the nerveroot, such as within the intervertebral foramen. Variations of measuringdevices may be inflatable, expandable, calibrated to a known shape/size,moldable/formable, or any combination of these. As mentioned, any ofthese variations may be adapted for bimanual use, and may includeneurostimulation to determine position and/or to determine the size ofthe region adjacent to the nerve.

With reference now to FIGS. 272 and 273, two portions of a lumbar spineare shown, similar to those shown in FIGS. 269 and 270. As mentionedabove, it may be desirable before, during or after a spine tissueremoval procedure, such as a procedure performed with device 8010 ofFIG. 271 or with any other suitable device, to measure one or moreintervertebral foramina to help determine how complete the procedure isand/or how much additional tissue might ideally be removed. In FIGS. 272and 273, an expandable foramen measurement device 8030 is shown in crosssection within an intervertebral foramen 807. In FIG. 272, where thereis no nerve root impingement and plenty of room in foramen 807, device8030 can expand to a larger size, compared to its expansion in FIG. 273,where bone and ligamentum flavum tissue has grown into foramen 807 andimpinged on nerve root 806. By measuring an amount of fluid passableinto device 8030 and/or by imaging the expandable portion of device 8030using radiographic methods, one may measure an intervertebral foramen807 before, during and/or after a spinal decompression procedure togauge how complete the procedure is and/or how much additional tissuewould ideally be removed.

FIGS. 274A and 274B illustrate one variation of a device 8032 formeasuring an intervertebral foramen (IF). This variation includescalibrated (preformed to a known shape/size) sounds, and is shown inperspective view in FIG. 274A, and illustrated in position in a spine inFIG. 274B. In one embodiment, device 8032 includes a flexible wire 8034at (at least) the distal end of the device, multiple sounds 8036 (or“sound members”) fixedly coupled with wire 8034, and a guidewire coupler8038. The sound members may be preformed to a known (calibrated)diameter, and/or shape. Various embodiments of guidewire coupler 8038,and methods for using them to couple a device with a guidewire, aredescribed in greater detail, for example, in U.S. patent applicationSer. No. 11/468,247, now U.S. U.S. Pat. No. 7,857,813, which waspreviously incorporated by reference. In FIG. 274B, device 8032 is shownin a spine, coupled with a guidewire 8039. Guidewire 8039 may be used topull device 8032 into a spine percutaneously or through a minimallyinvasive incision, thus obviating the need for the large incision,laminectomy and/or laminotomy required for using prior art devices.

In various embodiments, device 8032 may include any number of sounds8036, each having any suitable shape and diameter. In the embodimentshown, for example, sounds 8036 have a slightly tapered, bullet-likeshape and are labeled with numbers 1-5. In some embodiments, such numberlabels may be radiopaque so as to be easily visible via intraoperativefluoroscopy. In other embodiments, sounds 8036 may be completelyradiopaque. Sounds 8036 may have a tapered shape to facilitate theirpassage into an intervertebral foramen (IF) and between nerve root (NR)and impinging tissue. In other embodiments, sounds 8036 may becylindrical, ovoid, spherical, square, rectangular or any of a number ofshapes. In some embodiments, sounds 8036 may increase in size alongflexible wire 8034. For example, in one embodiment, sounds 8036 may havediameters of approximately 1 mm, 2 mm, 3 mm, 4 mm and 5 mm. In variousembodiments, any number of sounds 8036 may be coupled with flexible wire8034, such as but not limited to between two and twenty sounds 8036. Thesize of an intervertebral foramen may be assessed or approximated bydetermining the largest sound 8036 that can pass into the foramen. Thismay be determined, in various embodiments, by tactile feel, radiographicimaging, depth markers on flexible wire 8034 and/or the like. In variousembodiments, sounds 8036 and wire 8034 may be made of any suitablematerial, such as but not limited to metals, such as stainless steel andNitinol, or polymers. In some embodiments, sounds 8036 may be completelyrigid, such as those made of stainless steel, while in alternativeembodiments sounds 8036 may have some amount of “give” or flexibility,for example sounds made of a compliant polymer or filled with a gel orfluid.

In an alternative embodiment, device 8032 may be passed into the spineover a guidewire and may, thus, include a guidewire lumen. Any of thedevices or systems described herein may be adapted so that they can beeither passed over a guidewire. In some variations the devices areadapted to be pulled into a spine behind a guidewire, as mentionedbefore.

FIG. 275 is an alternative embodiment, including a system 8040 formeasuring a foramen, and includes multiple sound devices 8042, 8052,8062, 8072. Each sound device 8042, 8052, 8062, 8072 may include aflexible wire 8044, 8054, 8064, 8074, a sound 8046, 8056, 8066, 8076fixedly coupled with the wire, and a guidewire coupler 8048, 8058, 8068,8078 disposed at or near a distal tip of the wire. As with thepreviously described embodiment, sounds 8046, 8056, 8066, 8076 may haveany size and shape. In one embodiment, system 8040 may include multipledevices 8042, 8052, 8062, 8072 with gradually increasing sizes of sounds8046, 8056, 8066, 8076, so that each device may be passed sequentiallyinto a spine to determine the largest sound that may pass into anintervertebral foramen. In various embodiments, any number of devices8042, 8052, 8062, 8072 having any sizes of sounds 8046, 8056, 8066, 8076may be provided, such as but not limited 1 mm, 2 mm, 3 mm, 4 mm, sounds,etc. In this embodiment, each sound device 8042, 8052, 8062, 8072 isinserted and then removed before the next largest device is inserted.

With reference to FIG. 276, in another variations, a foramen measurementdevice 8080 includes a flexible wire 8082 (at the distal end), multiplesounds 8084 slideably disposed over wire 8082, a pusher 8086 slideablydisposed over wire 8082, and a guidewire coupler 8088 for attachingdevice 8080 to a guidewire 8089. In this embodiment, sounds 8084 ofincreasing diameter may be advanced into a spine and into a foramenusing pusher 8086, and sounds 8084 may be used to determine anapproximate size of the foramen as discussed above. In this embodiment,device 8080 may remain in place in the spine while sounds 8084 areadvanced sequentially along it into the foramen.

In some variations, the measurement device includes a tapered ortapering region that is calibrated to determine the minimum diameter ofthe intervertebral foramen. For example, FIG. 277 shows anotheralternative embodiment of an intervertebral measurement device 8090 thatincludes a flexible wire 8092, a long, tapered sound member 8094 fixedlycoupled with wire 8092, and a guidewire coupler 8096 distal tip 8096.The tapering sound member may be flexible (e.g., along the length). Thesound member 8094 may include multiple radiopaque markers 8095, so thatsound 8094 may be passed into an intervertebral foramen until it cannotpass any further, and a radiographic image may then be taken (such as byfluoroscopy) to determine an approximate size of the foramen. In this oranother embodiment, depth markers may also be placed on wire 8092 tohelp determine how far sound 8094 is able to pass into a foramen. Insome cases, device 8090 may be used not only to measure an approximatesize of a foramen but may also be used to dilate a space within theforamen, thus making it easier to pass subsequent instruments, such as atissue removal device.

FIG. 278 is another embodiment of a measuring device 80100 whichincludes a flexible wire 80101, an expandable portion 80104, an expander80105 slideably disposed over wire 80101 and within expandable portion80104, a pusher 80102 for advancing expander 80105 along wire 80101, anda guidewire coupler 80106. As mentioned previously, in alternativeembodiments, device 80100 may include a guidewire lumen rather thanguidewire coupler 80106 and may thus be passed over a guidewire into thespine rather than being pulled behind a guidewire. In use, expandableportion 80104 may be advanced partway into an intervertebral foramen,and then expander 80105 may be advanced within expandable portion 80104using pusher 80102 to expand expandable portion 80104. Usingradiography, depth markers and/or the like, a user may determine anapproximate size of the intervertebral foramen based on how far expander80105 can be advanced along wire 80101. As used in the presentapplication, “approximating the size” of a foramen may meanapproximating a cross-sectional area of the foramen, a volume of theforamen, a height or width of the foramen at one or more points, anamount of room a nerve root has within a foramen, and/or across-sectional area, volume, height or width of a portion of theforamen. In various embodiments, expandable portion 80104 may beentirely radiopaque or include radiopaque markers and may be eitherclosed on all sides or comprise two layers of material that expand awayfrom one another.

Measuring devices may also include inflatable or expandable regions. Forexample, FIGS. 279A and 279B show another embodiment of a device 80110for measuring an intervertebral foramen that includes an elongateflexible catheter 80114 coupled with a fluid source 80112 at itsproximal end, having an inflatable balloon 80116 at or near its distalend, and having a guidewire coupler tip 80118. Device 80110 may becoupled with a guidewire 80117, which may in turn be coupled with adistal handle 80119, and in some embodiment guidewire 80117 and distalhandle 80119 may be provided with device 80110 as a system. In useinflatable balloon 80116 portion of catheter 80114 may be advanced intoan intervertebral foramen in its deflated state by pulling it behindguidewire 80117. Fluid 80113 may then be passed into inflatable balloon80116, such as by depressing syringe 80112. The volume of anintervertebral foramen may be approximated, in one embodiment, bymeasuring the volume of fluid passed into inflatable balloon 80116.Alternatively or additionally, volume of the foramen may be approximatedby taking a radiographic image and using a radiopaque fluid 80113, suchas a contrast dye. Catheter 80114 and balloon 80116 may be made of anysuitable material commonly known or hereafter discovered, such as anysuitable polymer.

FIG. 279B shows a side view of a spine with the inflatable balloon 80116of device 80110 shown in cross section in an intervertebral foramen 807,along with nerve root 806. As is visible in this figure, balloon 80116may sometimes conform to a shape of the foramen, thus providing a moreaccurate approximation of the size of the foramen than a rigid device.

With reference now to FIG. 280, in another embodiment, an intervertebralforamen measurement device 80120 may include an elongate catheter 80122with a compartmentalized proximal balloon 80124, a compartmentalizeddistal balloon 80126, and a guidewire coupler tip 80128. Distal balloon80126, for example, may have three compartments, to approximate the sizeof the vertebral central canal 80126 c, lateral recess 80126 b andforamen 80126 a. In one embodiment, each of those three compartments isreplicated in proximal balloon 80124, and fluid may be transferred underpressure from proximal balloon 80124 to distal balloon 80126. As thecompartments of proximal balloon 80124 empty, the compartments of distalballoon 80126 fill until they can no longer fill because they havereached the size of the anatomical structures in which they reside.Thus, the size/volume of the proximal balloon 80124 may provide areadout of the foramen by correlating with the size of the distalballoon component, without requiring the use of a visualization methodsuch as fluoroscopy. The proximal balloons form a negativerepresentation of distal balloon 80126, thus reflecting the size andshape of the foramen, lateral recess and central canal. Compartments80124 a, 80124 b, 80124 c, 80126 a, 80126 b, 80126 c may be separated,for example, by valves.

Another inflatable or expandable variation of a measuring device isillustrated in FIG. 281A. In this example, the intervertebral foramenmeasurement device 80130 includes an elongate catheter 80132, aninflatable balloon 80133 disposed at or near a distal end of catheter80132, multiple electrodes 80134, 80134′ 80135, 80135′ coupled withballoon 80133, and a guidewire coupler 80136 disposed at or near adistal tip of device 80130. Balloon 80133 may be passed into anintervertebral foramen in a deflated state (e.g. by pulling it intoposition from the distal end of the guidewire). The measuring device maythen be inflated to assume the shape of the foramen by passing a fluid,such as saline or any other biocompatible fluid, through catheter 80132into balloon 80133. Once balloon 80133 is inflated with fluid, currentmay be passed between various pairs of the electrodes (i.e., 80134,80134′ and/or 80135, 80135′), and electrical properties measured toderive the distance between the electrodes. For example, the currentpassing between the electrodes may be analyzed to determine the rate ofcurrent passage between various electrodes to approximate the spacing ofthe electrodes, based on the known electrical properties of the fluidfilling the (insulating) balloon. This may be used to derive distancesbetween various electrode pairs over the balloon 80133. Multipleelectrodes may then be used to reconstruct a 3-dimensional image ofballoon 80133, thus approximating a shape of the foramen in which it hasbeen inflated.

Similarly, FIG. 281B illustrates another variation of a measurementdevice in which current may be applied between two (or more) electrodes80137, 80138 within an insulated balloon that has been inflated withinthe intervertebral foramen. Saline or other conductive material may beused to fill/inflate the balloon, and the volume of the balloon may bedetermined by the electrical properties. For example, an impedancemeasurement (taken at one or more frequencies) may be used to determinethe volume within the balloon.

FIG. 281C shows another example of an inflatable device. In thisvariation, the device includes an inflatable region 80143 located at thedistal region of the device 80140. The distal end of the device includesa coupler 80148 for coupling to a guidewire. A flexible catheterincluding an inflation lumen connects the inside of the balloon to theproximal end of the device. A transducer 80146 is positioned within theballoon. The transducer is configured to rotate (e.g., on a central axisor wire) to allow measurement of the distance to the inside of theballoon, from which the volume of the inflated balloon can bedetermined. In some variations the transducer is an optical transducer(e.g., camera), in other variations the transducer is an ultrasoundtransducer, or other modality transducer that may allow determination ofthe distance around the balloon.

With reference now to FIGS. 282A and 282B, in another alternativeembodiment, an intervertebral foramen measurement device 80150 mayinclude elongate catheter proximal 80154 and distal 80156 portions withan expandable mesh 80152 disposed between the two. In use, device 80150may be inserted into a patient and mesh 80152 advanced into anintervertebral foramen in its unexpanded state, as shown in FIG. 282A.Proximal portion 80154 and distal portion 80156 may then be pushedtoward one another to expand mesh 80152 to assume the approximate shapeof the foramen. Mesh 80152 may be made of radiopaque material, and thusa radiographic image may be acquired (using intraoperative fluoroscopy,for example) to help approximate the size of the foramen. In someembodiments, multiple images may be taken, such as lateral,anterior-posterior and/or oblique views, to help approximate a shape ofthe foramen. In an alternative embodiment, it may be possible to pull onproximal portion 80154 and distal portion 80156 to expand mesh 80152.Mesh 80152 may comprise any suitable material, such as stainless steel,any other metal, polymer or the like. The distal end of this variationof a measurement device may be configured to couple with a guidewire sothat it can be pulled through the intervertebral foramen and positionedtherein. In some variations the guidewire may be coupled to the deviceso that it pressure can be applied distally (e.g., pushing against thedistal end). In other variations the distal end of the device isconfigured to exit the subject so that it can be grasped and pressurecan be applied thereto.

FIG. 283 illustrates another variation of an expandable measurementdevice. In this embodiment the device 80160 for foramen measurementincludes an expandable pouch 80162 (or expandable catheter), multipleexpansion members 80164 (such as flexible wires, plates or the like),and a guidewire tube 80166 (or guidewire lumen) coupled with pouch80162, so that device 80160 may be advanced into a patient's body over aguidewire 80168. A distal portion of pouch 80162 may be advanced into anintervertebral foramen in an unexpanded state, with no expansion members80164 residing therein (or with few expansion members 80164), and theexpansion members 80164 may be passed into pouch to cause it to expand.The size (e.g., inner diameter) of an intervertebral foramen may beapproximated by the number of wires or other expansion members 80164that can be passed into pouch 80162. Additionally or alternatively, insome embodiments, pouch 80162 and/or expansion members 80164 may beradiopaque and may therefore be imaged using radiographic imagingtechnique(s) to help approximate the size and/or shape of the foramen.Pouch 80162 may be made of any expandable material, such as any of anumber of different polymers. Expansion members 80164 may be made of anysuitable material, such as but not limited to stainless steel, Nitinol,other metals, polymers or the like.

Any of the measurement devices described herein may be included as partof a system for decompressing nerves in the intervertebral foramenincluding a guidewire and a tissue removal device as described above. Insome variations, the measurement device may be part of a tissue removaldevice. For example, FIG. 284 illustrates a tissue removal device 80170including a measurement feature. The tissue removal device is similar tothat shown in FIG. 271. FIG. 284 shows a distal portion of such a tissueremoval device 80170, which may include a substrate 80172 having upperand lower surfaces, multiple blades 80174 formed from substrate 80172,an aperture 80175 (or “opening”) formed in substrate 80172, a tissuecollection pouch 80178 disposed under the lower surface of substrate80172 in fluid communication with aperture 80175, and a guidewirecoupler 80176. In this embodiment, tissue (such as ligamentum flavum,other soft tissue and/or bone) cut with blades 80174 may pass throughaperture 80175 into pouch 80178, thus expanding pouch 80178. As pouch80178 expands, it may become increasingly difficult to reciprocatedevice 80170 in the foramen, thus indicating to a user that a sufficientamount of tissue has been removed and the procedure is complete. In someembodiments, all or a portion of pouch 80178 may be radiopaque, so thatas it expands a radiographic image may be taken of it to approximate asize and/or shape of the foramen.

Referring to FIG. 285, in an alternative embodiment, a tissue removaldevice 80180 may include an upper layer 80182 and a lower layer 80183.An aperture 80185 and multiple blades 80184 may be formed in upper layer80182, such that aperture opens into a pouch 80188 formed by lower layer80183. Device 80180 may also include a guidewire coupler 80186. Device80180 may work similarly to the previously described embodiment, withthe size and/or shape of an intervertebral foramen being approximated bysize and/or shape of pouch 80188 as it fills, either by tactilefeedback, radiographic images or both. In this or the previousembodiment, it may also be possible to remove device 80180 (or 80170)from the patient to directly visualize the size of pouch 80188 (or80178) and/or to remove tissue from pouch 80188 to assess its amount.

With reference now to FIG. 286, in another alternative embodiment, atissue removal device 80190 may include a substrate 80192, multipleblades 80194, an aperture 80195, a guidewire coupler 80196 and a sidetissue collection pouch 80198. In this embodiment, pouch 80198 may be influid communication with aperture 80195 but may be disposedasymmetrically on a side of lower surface of substrate 80192, such thatas pouch 80198 fills with cut tissue, it pushes device 80190 toward anopposite side of an intervertebral foramen. This may facilitateside-to-side/lateral movement of device 80190 within an intervertebralforamen, which may help device 80190 to remove a greater amount oftissue. The size and/or shape of the foramen may be assessed via pouch80198 as in the previously described embodiments.

As mentioned briefly above, any of the devices for measuring theintervertebral foramen may include neural stimulation. In particular,the device may include one or more tight bipole pairs configured to emita localized stimulation field capable of activating a nearby nerve(e.g., the nerve root). Multiple bipole pairs may be associated withspecific regions of the measurement device. Activation of the “tight”bipole field in a particular region will stimulate only a nearby (e.g.,adjacent) nerve. A tight bipole field may be emitted when the bipolepairs are configured so that they are close to each other and arestimulated so that the current passed between the bipole pairs does notradiate substantially (i.e., less than a few millimeters from thesurface of the measurement device). Thus, the nerve will be stimulatedonly when it is substantially close to the device (e.g., within contactor less than a 1 mm). Stimulation of the device may be detected by anyappropriate methods, including (but not limited to) EMG measurementtaken from the patient.

FIGS. 287A to 287C illustrate one variation of a measurement device802000 including neural stimulation. In this example, the measurementdevice includes a tapered measurement probe. A handle may be located tothe proximal end of the measurement device. The shaft portion 802003extends distal to the handle; the distal region of the measurementdevice is tapered, and the very distal end of the device may include acoupling tip 802005 for coupling to a guidewire. The tapered region istypically divided up into different regions or zones 802001. Each zonemay be a measurement region, having a specific diameter or range ofdiameters. For example, the taper in a specific region may be veryslight. The zones may be marked with radio opaque bands or makers whichallow the zones to be distinguished. Each zone may also include one ormore bipolar pairs (e.g., tripolar pairs or a line of bipolar pairs)that may be activated by a stimulator 802020 to emit a bipole filed.Each of these zones or sections may be individually addressed (e.g.,activated) by the stimulator or controller 802020.

FIG. 287B illustrates one variation of the distal region of ameasurement device having neural stimulation. In this example, thedistal end has a width that is less than the height (thickness), whichmay allow the device to more readily fit within the foramen. The distalend is divided up into different zones or regions that arelongitudinally separated. In some variations, the zones or regions arealso divided up into top/bottom/left side/right size sub-regions. Any ofthese zones/regions and sub-regions may be activated separately or atthe same time. For example, all of the sub-regions of a particularlongitudinal region may be activated at once. In some variations, eachzone or sub-region includes a plurality of cathodes and anodes. Each ofthe anodes and/or cathodes may be separately connectable to a stimulator802020 for controlled activation of a specific pair, or they may begrouped. For example, all of the anodes in one zone or sub-region may beconnected to or part of the same anode. Similarly, all of the cathodesin one zone or sub-region may be connected to or part of the samecathode 802010. This may help reduce or simplify wiring of the device.

Because of the very small spacing between the bipole pairs (ortripoles), the device may precisely detect contact with a nerve. Thebipole broadcast distance may be adjusted by varying the spacing of thebipoles, and/or the size of the bipoles. For example, the spacingbetween adjacent bipole pairs (anode and cathodes) may be less than 2mm, less than 1 mm, less than 0.5 mm, etc. The surface area of eachexposed anode/cathode may be less than 1 mm2, less than 0.5 mm2, etc.FIG. 287C illustrates the bottom side of the measurement probe shown inFIG. 287B. In FIGS. 287B and 287C, the bottom size may include morebipole pairs per zone. In some variations, it is expected that the nervewithin the intervertebral foramen will be located on this side (e.g.,anterior to the patents body) during the procedure.

A measurement device including neural stimulation may be included aspart of a system or kit, as mentioned above. FIG. 288 illustratesvarious components that may be included as part of a kit or system. Forexample, a kit or system may include a measurement probe with electricalbipoles 802101, and connections to a stimulator or controller 802110.The kit may also include a probe 802102 (e.g., a telescoping, curvingprobe) for positioning and delivering a guidewire 802103. The guidewiremay include a sharp or pointed distal tip and a proximal end configuredto be coupled to one or more devices. A handle 802104 may also beincluded for attaching to the distal end of the guidewire, as describeabove with respect to FIG. 271. An EMG system (or subsystem) includingan EMG reader 802105 and one or more probes or electrodes 802106, mayalso be included. The measurement probe may be a tapered probe, asillustrated in FIGS. 287A-288, or it may be configured as any of themeasurement devices illustrated above including tight bipole pairs.

In operation, the measurement device may be inserted using the bimanualmethod described briefly above. For example, after introducing aguidewire from a first location outside of the patient, into and throughthe intervertebral foramen, and out of the patient at a second location,the proximal end of the guidewire may be coupled to the measurementprobe. The guidewire may then be pulled (e.g., after attaching a handle)to draw the measurement probe through the intervertebral foramen. Anexemplary illustration is provided in FIG. 289 for one variation of themeasurement device. In this example, the measurement device is tapered,with marked regions each including neural stimulation that can beindividually addressed. The distal end of the measurement device isdrawn through the intervertebral foramen by pulling on the distal end(in this example, via the coupling to the guidewire).

In some variations, the measurement device may be pulled through theforamen until it cannot be advanced any further. The diameter of theforamen may then be estimated based on the marks on the measurementdevice. Neural stimulation can be used to determine the approximatediameter of the foramen adjacent to the nerve. Since decompression ofthe nerve (nerve root) is on goal of this procedure, it may beparticularly important to know the diameter of this region. Byselectively activating the bipole pairs nears in each zone, the zonenearest the nerve can be determined, and therefore the approximatedimension of the intervertebral foramen nearby (which must be at leastas large as this zone or region).

In some variations, the measurement device may be advanced whilestimulating the bipoles along the entire device. Since the bipole fileddoes not extend substantially from the surface of the device, neuralstimulation of the nerve root will indicate when the device isapproaching the nerve. This is illustrated in FIGS. 290A and 290B. Forexample, in FIG. 290A the bipole field originating from the measurementdevice 802301 does not activate the nerve 802303 because it is too farfrom the nerve to induce activation of the nerve. As the measuringdevice is advanced, and the taper of the device widens, the bipole filedapproaches the nerve 802303 until it is stimulated, as indicated in FIG.290B. By advancing the measurement device in this manner, (e.g., slowly)the size of the decompressed foramen may be estimated without damagingthe nerve. Once activation has occurred, individual zone or regions ofthe measurement device may be stimulated to determine which zone orregion is nearest to the nerve, and therefore what the approximate sizeof the foramen is.

FIGS. 291A to 291C illustrate another variation of a measurement device802401, including a shapeable or formable region at the distal portionof the device. In this example, the distal end is tapered. This soundregion may be made of any appropriate, formable material. For example,the material may be a polymer. In some variations, the sound is made ofa clay-like material (either synthetic or non-synthetic). For example,the sound may be made of a material that is moldable such as siliconeplastic (putty of silicone and boric acid), or the like. Other exemplarymaterials may include PET, PE, PP, Urethone, FP, PTFE, Nylon, andco-polymers of any of these.

In some variations the measurement device includes a moldable inner corethat is surrounded by a liner or outer film. This outer film or linermay be lubricious, and may eliminate direct contact between the moldablematerial and the patient's tissue.

FIGS. 291B and 291C illustrate one method of operation of a measurementdevice including a moldable or formable sound. As described above, thedevice may be used with a guidewire. For example, the distal end of themeasurement device may include a coupler for coupling to the proximalend of a guidewire, so that the measurement device can be pulled throughthe foramen. In some variations the measurement device includes aguidewire lumen so that the device can be slid over the guidewire. InFIG. 291B, the measurement device 802401 is pulled through theintervertebral foramen 802403 by the guidewire 802407. The tapered endpasses through the foramen, until the device is snuggly fitted into theforamen. This snug fitting may be determined by some minimum amount offorce applied to draw it through the device. For example, the device maybe limited to less than a few pounds of applied force (e.g., less than10 lb of tension, less than 5 lbs of tension, less than 1 lb of tension,etc.). The measurement device may then be withdrawn by pulling on theproximal end of the measurement device (withdrawing the guidewire backthrough the foramen). FIG. 291C illustrates one example of a moldablesound region of a measuring device that has been placed into anintervertebral foramen until it has conformed to the shape of theforamen.

In FIG. 291C, a portion of the tapered formable distal end has taken onthe shape of the intervertebral foramen 802405. The device will includea bulge near the proximal end where the material was prevented fromentering the constricted foramen, and the region distal to this willhave the maximum diameter shape of the narrowed region. A plateau regionmay be present, indicating the diameter of the foramen opening. Thismolded shape may then be measured to determine the dimensions, orcompared with earlier/later (e.g., post-decompression orpre-decompression) sounds. In some variations the molded shape may bemade permanent so that it can be later compared.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether.Furthermore, although many of the embodiments and variations describedare directed to measuring the intervertebral foramina, these devices maybe used or adapted for use in many other body openings, including otherforamina, including general neural foramen.

Optional features of various device and system embodiments may beincluded in some embodiments and not in others. These and many othermodifications may be made to many of the described embodiments.Therefore, the foregoing description is provided primarily for exemplarypurposes and should not be interpreted to limit the scope of theinvention as it is set forth in the claims.

Spinal Access System and Method

The present invention relates generally to medical/surgical devices andmethods. More specifically, the present invention relates to a spinalaccess system and method.

In recent years, less invasive (or “minimally invasive”) surgicaltechniques have become increasingly more popular, as physicians,patients and medical device innovators have sought to reduce the trauma,recovery time and side effects often associated with conventionalsurgery. Developing less invasive surgical methods and devices, however,poses many challenges. For example, less invasive techniques typicallyinvolve working in a smaller operating field, working with smallerdevices, and trying to operate with reduced or even no directvisualization of the structures being treated. These challenges areoften compounded when target tissues of a given procedure reside veryclose to one or more vital, non-target tissues.

One area of surgery which would likely benefit from the development ofless invasive techniques is the treatment of spinal stenosis. Spinalstenosis occurs when nerve tissue and/or the blood vessels supplyingnerve tissue in the spine become impinged by one or more structurespressing against them, causing symptoms. The most common form of spinalstenosis occurs in the lower (or lumbar) spine and can cause severepain, numbness and/or loss of function in the lower back and/or one orboth lower limb.

FIG. 1 is a top view of a vertebra with the cauda equina (the bundle ofnerves that extends from the base of the spinal cord) shown in crosssection and two nerve roots branching from the cauda equina to exit thecentral spinal canal and extend through intervertebral foramina (or“neural foramina”—singular “foramen”) on either side of the vertebra.Spinal stenosis can occur when the spinal cord, cauda equina and/ornerve root(s) are impinged by one or more tissues in the spine, such asbuckled or thickened ligamentum flavum, hypertrophied facet joint (shownas superior articular processes shown in FIG. 1), osteophytes (or “bonespurs”) on vertebrae, spondylolisthesis (sliding of one vertebrarelative to an adjacent vertebra), facet joint synovial cysts, and/orcollapse, bulging or herniation of an intervertebral disc. Impingementof neural and/or neurovascular tissue in the spine by one or more ofthese tissues may cause pain, numbness and/or loss of strength ormobility in one or both of a patient's lower limbs and/or of thepatient's back.

In the United States, spinal stenosis occurs with an incidence ofbetween 4% and 6% of adults aged 50 and older and is the most frequentreason cited for back surgery in patients aged 60 and older. Patientssuffering from spinal stenosis are typically first treated withconservative approaches such as exercise therapy, analgesics,anti-inflammatory medications, and epidural steroid injections. Whenthese conservative treatment options fail and symptoms are severe, as isfrequently the case, surgery may be required to remove impinging tissueand decompress the impinged nerve tissue.

Lumbar spinal stenosis surgery involves first making an incision in theback and stripping muscles and supporting structures away from the spineto expose the posterior aspect of the vertebral column. Thickenedligamentum flavum is then exposed by complete or partial removal of thebony arch (lamina) covering the back of the spinal canal (laminectomy orlaminotomy). In addition, the surgery often includes partial or completefacetectomy (removal of all or part of one or more facet joints), toremove impinging ligamentum flavum or bone tissue. Spinal stenosissurgery is performed under general anesthesia, and patients are usuallyadmitted to the hospital for five to seven days after surgery, with fullrecovery from surgery requiring between six weeks and three months. Manypatients need extended therapy at a rehabilitation facility to regainenough mobility to live independently.

Removal of vertebral bone, as occurs in laminectomy and facetectomy,often leaves the affected area of the spine very unstable, leading to aneed for an additional highly invasive fusion procedure that puts extrademands on the patient's vertebrae and limits the patient's ability tomove. Unfortunately, a surgical spine fusion results in a loss ofability to move the fused section of the back, diminishing the patient'srange of motion and causing stress on the discs and facet joints ofadjacent vertebral segments. Such stress on adjacent vertebrae oftenleads to further dysfunction of the spine, back pain, lower leg weaknessor pain, and/or other symptoms. Furthermore, using current surgicaltechniques, gaining sufficient access to the spine to perform alaminectomy, facetectomy and spinal fusion requires dissecting through awide incision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Thus, while laminectomy, facetectomy, and spinal fusion frequentlyimprove symptoms of neural and neurovascular impingement in the shortterm, these procedures are highly invasive, diminish spinal function,drastically disrupt normal anatomy, and increase long-term morbidityabove levels seen in untreated patients.

A number of devices, systems and methods for less invasive treatment ofspinal stenosis have been described by the assignee of the presentinvention. For example, various embodiments of such devices, systems andmethods are described in U.S. patent application Ser. Nos.: 11/250,332,entitled “DEVICES AND METHODS FOR SELECTIVE SURGICAL REMOVAL OF TISSUE,”and filed Oct. 15, 2005, now U.S. Pat. No. 7,738,968; 11/375,265,entitled “METHOD AND APPARATUS FOR TISSUE MODIFICATION,” and filed Mar.13, 2006, now U.S. Pat. No. 7,887,538; 11/251,155, entitled “DEVICES ANDMETHODS FOR TISSUE ACCESS” and filed Oct. 15, 2005, now Publication No.US-2006-0095028-A1; 11/952,934, entitled “TISSUE REMOVAL DEVICES ANDMETHODS” and filed Dec. 7, 2007, now Publication No. US-2008-0147084-A1;and 11/535,000, entitled “TISSUE CUTTING DEVICES AND METHODS,” and filedSep. 25, 2006, now Publication No. US-2008-0033465-A1, all of whichapplications are hereby incorporated fully by reference herein.

One challenge in treating spinal stenosis using minimally invasive toolsis accessing the small, confined spaces of the spine to addressimpinging tissues. In conventional surgical approaches, as mentionedabove, access is generally gained by performing a laminotomy orlaminectomy in the vertebrae. Even in these open surgical approaches, itis often difficult or impossible to see or reach an intervertebralforamen where tissue may be impinging a nerve root. In less invasiveprocedures, accessing an intervertebral foramen is usually even moredifficult.

A number of devices, systems and methods for accessing target tissue inthe spine and identifying neural tissue have been identified. Forexample, tissue access is addressed in U.S. patent application Ser.Nos.: 11/251,205, entitled “DEVICES AND METHODS FOR TISSUE ACCESS,” andfiled Oct. 15, 2005; 11/457,416, entitled “SPINAL ACCESS AND NEURALLOCALIZATION,” and filed Jul. 13, 2006 now U.S. Pat. No. 7,578,819; and11/468,247, entitled “TISSUE ACCESS GUIDEWIRE SYSTEM AND METHOD,” andfiled Aug. 29, 2006, now U.S. Pat. No. 7,857,813, all of whichapplications are hereby incorporated fully by reference herein. Assigneeof the present invention has described a number of devices, systems andmethods for removing or otherwise treating target tissue in the spine inU.S. patent application Ser. Nos.: 11/251,165, entitled “DEVICES ANDMETHODS FOR TISSUE MODIFICATION,” and filed Oct. 15, 2005, now U.S. Pat.No. 7,553,307; 11/375,265, entitled “METHODS AND APPARATUS FOR TISSUEMODIFICATION,” and filed Mar. 13, 2006, now U.S. Pat. No. 7,887,538;11/535,000, entitled “TISSUE CUTTING DEVICES AND METHODS,” and filedSep. 5, 2006, now Publication No. US-2008-0033465-A1; and 11/687,558,entitled “Flexible TISSUE REMOVAL DEVICES AND METHODS,” and filed Mar.16, 2007, now U.S. Pat. No. 8,062,298; all of which applications arehereby incorporated fully by reference herein. Although the inventionsdescribed in these applications solve many of the challenges associatedwith minimally invasive or less invasive spinal access, furtherinnovations and improvements are always desirable.

Therefore, it would be desirable to have improved systems and methodsfor accessing a spine. Ideally, such systems and methods would work in aminimally invasive, less invasive and/or percutaneous access settings,without requiring large incisions, laminotomies, laminectomies, ordirect visualization of the site to be accessed. In some cases, it maybe ideal to provide access to one or more intervertebral foramina of thespine, while it may also or alternatively be desirable to provide accessto the central spinal canal. At least some of these objectives will bemet by the present invention.

Described herein are systems, devices, tools and methods for accessing apatient's spine, and particularly a patient's epidural space. Forexample, described herein are tissue locking cannulas, ligamentum flavumaccess tools, and systems including one or both of these in addition toguide probes, guidewires, and tissue modification devices, particularlybimanual tissue modification devices.

In various embodiments, the systems, devices, and methods may be used inpercutaneous, minimally invasive or less invasive surgical procedures.Alternatively, these devices, systems and methods may also beadvantageous for use in an open surgical setting. While these devices,systems and methods are described primarily with reference to their usesin the spine, in some embodiments they may also be useful for accessingother parts of the body in percutaneous, minimally invasive and/or lessinvasive surgical procedures.

With reference now to FIG. 292, a cross-sectional view of a spine isshown, with one embodiment of a spinal access system 8510 extendingthrough a patient's skin and into the spine. Shown in the figure are avertebra V, the cauda equina CE, the epidural space ES, twointervertebral foramina IF, and ligamentum flavum LF of the spine. Inone embodiment, spinal access system 8510 may include a tissue lockingcannula 8512, including a handle 8514, a cannula shaft 8516, and atissue coupler 8518 disposed at the distal end of shaft 8516 forcoupling with ligamentum flavum LF tissue (or additionally oralternatively periosteum of the vertebral bone and/or vertebral bone).System 8510 may also include a blunt-ended probe 8520, which may slidethrough cannula 8512 and through ligamentum flavum LF to position adistal portion of probe 8520 in the epidural space ES of the spine. Insome embodiments, system 8510 may further include a curved, cannulated,at least partially flexible guide member 8522, which may slide throughprobe 8520 to extend its curved distal portion into the epidural spaceES and at least partway into (and in some cases completely through) anintervertebral foramen IF. Optionally, guide member 8522 may include apusher member 8523 for facilitating advancement of guide member 8522through probe 8520. In some embodiments, system may further include oneor more guidewires 8524, which may be advanced through a lumen of guidemember 8522 to extend through an intervertebral foramen IF and throughthe patient's skin. Alternatively, guidewire 8524 may be providedseparately, apart from system 8510. While in some embodiments, system8510 may be used to place one or more guidewires 8524 through one ormore intervertebral foramina IF, in other embodiments, system 8510 maybe used to access an epidural space ES and possibly one or moreintervertebral foramina IF for one or more other purposes, such as toprovide access for a visualization device, to introduce a drug or othermaterial or substance and/or the like.

The various components of spinal access system 8510 may be made of anyof a number of suitable materials and combinations of materials. Forexample, in some embodiments, cannula 8512 may be made of a combinationof stainless steel and plastic or other polymer. In some embodiments,both guide member 8522 and guidewire 8524 may be made of Nitinol.Alternatively, guide member 8522 may be made of a polymer, such as PEEK,and guidewire 8524 may be made of Nitinol. Probe 8520 may be made ofstainless steel, Nitinol, other metals, or any other suitable material.

In alternative embodiments, access system 8510 may include fewer oradditional components. For example, in one embodiment probe 8520 may notbe included, and guide member 8522 may pass directly through tissuelocking cannula 8512 and partway into or through an intervertebralforamen IF. Other embodiments may include multiple guide members 8522,each having a curved distal portion with a different radius of curvatureto accommodate different patient anatomies. In some embodiments, pushermembers 8523 may be provided for any or all of probe 8520, guide member8522 and guidewire 8524, to facilitate passage of these componentsthrough one another. In some embodiments, these pusher members 8523 maybe removeably attachable, while in alternative embodiments they may befixedly attached to their respective components.

Referring now to FIG. 293, one embodiment of a spinal access system 8530is shown in greater detail. In this embodiment, access system 8530 mayinclude a number of different components, such as a tissue lockingaccess cannula 8532. Access cannula 8532 may include a hollow shaftportion 8534 with a tissue locking distal end 8536 and a proximal hub8540 (or “handle”), which may be partially hollow and contain a spring8542 and a needle release button 8544. Locking distal end 8536 may, insome embodiments, include two or more tissue locking barbs 8538,configured to lock into tissue when cannula 8532 is rotated in onedirection about its longitudinal axis and to release from tissue whencannula 8532 is rotated in the opposite direction. In some embodiments,tissue locking may also require application of forwardly directed (ordistally directed) pressure, to thus press and rotate cannula 8532 intotissue. Alternatively, only rotation, without forwardly directedpressure, may be required in some embodiments. Barbs 8538 may have anysuitable shape and may range in number from two to as many as ten ormore in various alternative embodiments. In fact, some embodiments mayhave only one barb 8538 or more than ten, although multiple barbs 8538may be more efficacious than just one at attaching to tissue and morethan ten barbs 8538 may unnecessarily complicate manufacturing andinhibit attachment of cannula 8532 to tissue. Generally, barbs 8538 mayall point in the same direction, relative to the circumference ofcannula 8532, so that turning cannula 8532 in one direction attachesbarbs 8538 to tissue, and turning cannula 8532 in an opposite directionreleases barbs 8538 from the tissue. In various alternative embodiments,barbs 8538 may be configured to specifically attach to and release fromdifferent types of tissue. For example, in one embodiment, barbs 8538may be configured to specifically attach to ligamentum flavum tissue, inan alternative embodiment, barbs 8538 may be configured to specificallyattach to periosteum tissue, and in another alternative embodiment,barbs 8538 may be configured to attach to both ligament and periosteum.

Other variations of the tissue locking cannula 8534 may be used. Forexample, the tissue locking cannula may include one or more barbs oranchors that are located more proximally, either in addition, orinstead, of the distal barbs illustrated and described above. Forexample, the tissue locking member may include anchors, hooks or barbsthat are located proximal to the distal end. These anchoring members maybe configured to be secured to the local spinal anatomy, andparticularly the bony region (e.g., vertebra) or spinal muscle. In somevariations, the anchoring members are extendable from one or morepositions (e.g., ports) on the side of the cannula. For example, theanchors may be extendable from the cannula.

In one embodiment, cannula shaft portion 8534 may be made of onematerial, such as but not limited to stainless steel. In an alternativeembodiment, shaft portion 8534 may be made of multiple materials joinedtogether. For example, in one embodiment, as shown in the magnified viewof tissue locking portion 8536, a shaft proximal portion 8534 a, whichmay make up a majority of shaft 8534, may be made of a polymer or otherradio-translucent material. A smaller, distal shaft portion 8534 b maybe made of stainless steel, some other metal, or some non-metallicradiopaque material. In use, such a multi-material shaft 8534 a, 8534 bmay facilitate intraoperative radiographic monitoring of the location ofshaft distal portion 8534 b and thus tissue locking portion 8536 ofcannula 8532, such as by intraoperative fluoroscopy.

Spinal access system 8530 may also include an epidural needle 8546coupled with a sheath 8548 and proximal hub 8550, which may include alock ring 8551, and a stylet 8552 for residing in needle 8546 as it ispassed into a patient's body. Epidural needle 8546 and stylet 8552 may,for example, be similar to other known epidural needles and styletspresently available or hereafter conceived. Sheath 8548 may cover all ora portion of needle 8546 and may act to occupy space between the outerdiameter of needle 8546 and the inner diameter of cannula shaft portion8534, which may facilitate passage of cannula 8532 and needle 8546 intoa patient. Needle hub 8550 may fit partially within and lock intocannula hub 8540, such as by means of lock ring 8551, to removeablyattach needle 8546 and sheath 8548 to cannula 8532.

In one embodiment, cannula 8532 may be advanced into a patient withneedle 8546 and sheath 8548 residing within and attached to it and withstylet 8552 residing within needle 8546. As the epidural space of thespine is approached, stylet 8552 may be removed and a syringe 8554 maybe coupled with needle hub 8550 for performing a loss of resistanceneedle access of the epidural space. In one embodiment, once loss ofresistance is achieved, needle 8546 may be released from cannula 8532 bypressing release button 8544 on cannula hub 8540. In some embodiments,needle 8546 may be spring-loaded into hub 8540, so that when releasebutton 8544 is pressed, spring 8542 ejects needle 8546 proximally out ofcannula 8532 and thus ejects the distal portion of needle 8546 from theepidural space. This quick ejection method may help reduce the risk ofinjury to neural structures and/or dura by the sharp tip of needle 8546.

In some embodiments, spinal access system 8530 may also include acannulated, at least partially rigid probe 8555, which may slide throughcannula 8532 after needle 8546 is removed. This cannulated probe may beoptional. For example, a system may include just the tissue lockingcannula and a flexible guide member (or simply a guide wire) may beused. Probe 8555 may include a distal aperture 8556, which in someembodiments may be located at the extreme distal end of probe 8555, andmay also include a pusher member 8557 (or hub). In some embodiments, acurved, at least partially flexible guide member 8558 may be provided toslide through probe 8555, so that its curved distal portion extendsdistally out of distal aperture 8556 into an epidural space of apatient. Guide member 8558 may be cannulated and may include anatraumatic distal tip 8560 (having a bulb shape or alternativeatraumatic shapes in other embodiments) and a distal aperture 8562. Insome embodiments, system 8530 may also include a pusher member 8559 forfacilitating advancement of guide member 8558 through probe 8555. Pushermember 8557 may generally facilitate advancement of probe 8555 throughcannula 8532. In various embodiments, pusher members 8557, 8559 may beeither fixedly attached or removeably attachable to their respectivesystem components. Probe pusher member 8557, which may also include ahub, may facilitate attaching probe 8555 to cannula 8532 during use.

Probe 8555 and guide member 8558 may be made of any suitable material ormaterials. For example, in one embodiment, probe 8555 may be made of ametal, such as but not limited to stainless steel, and guide member 8558may be made of a different metal, such as but not limited to Nitinol. Inan alternative embodiment, guide member 8558 may be made of a flexiblepolymer, such as PEEK. Pushers 8557, 8559 may similarly be made of anysuitable material.

In an alternative embodiment, access system 8530 may include a differentprobe 8564 and guide member 8568. In this embodiment, probe 8564 mayhave a side-facing aperture through which curved, flexible guide member8568 passes. As mentioned above, this probe 8564 (similar to thecannulated probe 8555) is optional. Guide member 8568 may have a bluntdistal tip 8570, which may not have a ball tip as in the previouslydescribed embodiment and which may have a slit opening 8572 at itsextreme distal end. Thus, in various embodiments, guide member 8568 mayhave any of a number of different configurations and tip shapes. Again,probe 8564 may include a pusher member 8566 and/or guide member 8568 mayinclude a pusher member 8574.

With reference now to FIGS. 294A-294H, one embodiment of a method foraccessing a spine is described. As shown in FIG. 294A, in oneembodiment, a tissue locking cannula 8580 may be advanced through apatient's skin and into the patient over an epidural needle 8582 coupledwith a syringe 8584. In some embodiments, cannula 8580 may be advancedinto the patient over needle 8582 with a stylet in place through needle8582, and stylet may then be replaced with syringe 8584 once needle 8582is closer to the patient's spine. Although this step is not shown inFIGS. 294A-294H, it is a known technique in epidural needle placementand may be used in some embodiments. Alternatively, in some variations,the tissue-locking cannula is advanced either by itself, or over amember such as a ligamentum flavum access tool, as described in greaterdetail below. Variations in which a needle is not used may be preferred,because non-needle or blunt (atraumatic) members may be less likely todamage tissue beneath the ligamentum flavum.

Nevertheless, as shown in FIG. 294B, tissue locking cannula 8580 andneedle 8582 may be further advanced, using a loss of resistancetechnique, to pass a tip of needle 8582 through the ligamentum flavum LFinto the epidural space ES of the spine. Using a loss of resistancetechnique, syringe 8584 will typically depress once the epidural spaceES is reached with the tip of needle 8582, thus passing fluid throughthe needle tip (solid-tipped arrows).

Once the tip of needle 8582 reaches the epidural space ES, needle 8582may be quickly ejected or otherwise removed from cannula 8580, thusleaving only cannula 8580 in place within the patient, as shown in FIG.294C. Cannula 8580 may then be turned to lock a tissue locking distalend 8581 of cannula 8580 with spinal tissue, including ligamentum flavumand/or periosteum of vertebral bone. In one embodiment, needle 8582 willhave a length such that it will protrude a known distance out of cannuladistal end 8581. Thus, a surgeon or other user may know that when tip ofneedle 8582 reaches the epidural space ES, cannula distal end 8581 willreside in ligamentum flavum LF tissue. In some embodiments, placement ofdistal end 8581 in ligamentum flavum LF and/or bone periosteum may alsobe confirmed by radiographic evidence, such as fluoroscopy. Inalternative embodiments, cannula 8580 may be locked to spinal tissueafter needle 8582 is removed, as shown in the figures, or alternativelymay be locked to tissue before needle 8582 is removed. As mentionedpreviously, in some embodiments, needle 8582 may be removed from cannula8580 by pressing a spring-loaded release button on cannula 8580 to ejectneedle 8582 and then may be withdrawn the rest of the way out of cannula8580 manually by sliding needle 8582 out.

In some variations, after securing the cannula to the ligamentum flavum,the cannula may be withdrawn slightly (proximally) so that theligamentum flavum is “tented” by the action of the tissue lockingcannula For example, moving the tissue locking cannula proximally mayhelp move the ligamentum flavum so that cutting or piercing theligamentum flavum is less likely to damage underlying tissue.

In variations in which a needle or stylet is not used to penetrate theligamentum flavum (or periostium and/or bone) before locking the tissuelocking cannula, the distal end of the cannula may be placed against thetarget tissue, e.g., ligamentum flavum, by tactile feedback, byfluoroscopic positioning, by using anatomical landmarks (such as thepedicles, etc.), or any combination of these. For example, the cannulamay be advanced to the lamina by feel and/or fluoroscopy, and thenwalked over to the ligamentum flavum area and attached similar to FIG.294C. Thereafter, the ligamentum flavum may be penetrated by aligamentum flavum access device (described below) and/or a needle,stylet, or other element.

As shown in FIG. 294D, once tissue locking cannula 8580 is locked totissue, an at least partially rigid probe 8586 with a blunt tip may beadvanced through cannula 8580, to position the probe's tip in theepidural space ES. The blunt tip of probe 8586 may be configured toavoid damage to the cauda equine CE of the lumbar spine and other neuralstructures, such as nerve roots or spinal cord.

Referring to FIG. 294E, in one embodiment the method may next involveadvancing an at least partially flexible guide member 8588 through probe8586, perhaps with the help of a pusher member 8589. Guide member 8588may be advanced through probe 8586 to advance a curved distal portion ofguide member 8588 at least partway into, and sometimes all the waythrough, an intervertebral foramen IF of the spine.

With guide member 8588 in position, and referring now to FIG. 294F, aguidewire 8590 may be passed through guide member 8588 and back out thepatient's skin at a location apart from the entry location of cannula8580. In some embodiments, guide member 8590 may have a sharp distal tipto facilitate its passage through tissue and skin and may have a shapedproximal end for coupling guidewire with a tissue modification device tobe pulled into the patient. Such guidewires and methods for using themare described in greater detail, for example, in U.S. patent applicationSer. No. 11/468,247, which was previously incorporated by reference.

Once guidewire 8590 is placed through an intervertebral foramen IF,guide member 8588, probe 8586 and cannula 8580 may be removed from thepatient. As shown in FIG. 294G, in one embodiment, tissue lockingcannula 8580 may be removed by turning it in a opposite direction fromthe direction it was turned to lock it into the tissue. For example, ifturning cannula 8580 in a clockwise direction locks it to tissue,turning it in a counter-clockwise direction may unlock it from thetissue, or vice versa.

Finally, as shown in FIG. 294H, when cannula 8580 and the othercomponents of an access system are removed, guidewire 8590 may be leftbehind to extend into the patient, through an intervertebral foramen IFand back out of the patient. Guidewire 8590 may be then be used to passan instrument into the patient's spine to perform a procedure, such as aminimally invasive decompression procedure. Again, such passage ofinstruments is described in greater detail, for example, in U.S. patentapplication Ser. No. 11/468,247 (now U.S. Pat. No. 7,857,813). Use ofvarious instruments to perform procedures in the spine are described inpatent applications previously incorporated by reference, although thedevices, systems and methods described herein are not limited to the useof such instruments.

In various alternative embodiments, the method just described may haveany of a number of variations, such as fewer steps, additional steps,use of additional or different system components and/or the like. Forexample, in one alternative embodiment, the step of advancing probe 8586may be skipped, such that guide member 8588 may be passable throughcannula 8580 without use of probe 8586. In another alternativeembodiment, probe 8586 may have an articulating or bendable distalportion, and the step of advancing guide member 8588 may be skipped,such that guidewire is advanced directly through probe 8586, without useof guide member 8588. In yet another alternative embodiment, guidemember 8588 may be used to deliver some other substance or structureinto a spine, instead of or in addition to guidewire 8590. For example,one or more pharmaceutical agents may be delivered to an intervertebralforamen IF or other area in a spine using guide member 8586.

With reference now to FIGS. 295A-295G, a method for inserting analternative embodiment of a tissue locking access cannula 85100 isdescribed. In this embodiment, cannula 85100 may include a series ofcannulas having different diameters, with successive cannulas beinglarger to slide over previously placed cannulas. Using this method,spinal access may be obtained percutaneously or with a small incision,and successively larger cannulas may then be placed to provide wideraccess. For example, in one embodiment, a first tissue locking cannula85100 may first be passed into the patient to contact its locking distalend 85102 with ligamentum flavum LF tissue. In one embodiment, firstcannula 85100 may be advanced into the patient over a sylet, dilator orother device to prevent coring of tissue. Distal end 85102 may lock withtissue by turning it about its longitudinal axis, as describedpreviously. In one embodiment, a method for placing first cannula 85100may involve advancing it into a patient until distal end 85102 contactsa vertebral lamina and then moving (or “walking”) distal end 85102gradually off the lamina until it reaches soft tissue—i.e., ligamentumflavum LF. In an alternative embodiment, distal end 85102 may beattached to periosteum of a vertebral lamina. In yet another alternativeembodiment, distal end 85102 may be attached to both ligamentum flavumand periosteum.

As shown in FIG. 295B, once first cannula 85100 is attached toligamentum flavum LF (and/or other tissue), a second cannula 85104, alsohaving a tissue locking distal end 85106, may be passed over it into thepatient. In FIG. 295C, second cannula 85104 is turned to lock its distalend 85106 to ligamentum flavum LF, and first cannula 85100 may then beremoved. In alternative embodiments, first cannula 85100 may be removedbefore attaching second cannula 85104 to tissue.

In FIG. 295D, a third tissue locking cannula 85108 with a tissue lockingdistal end 85110 is advanced over second cannula 85104. In FIG. 295E,third cannula is turned to attach it to ligamentum flavum LF and secondcannula 85104 is removed through third cannula 85108, leaving thirdcannula 85108 attached to tissue and extending out of the patient, asshown in FIG. 295F. In some embodiments, as in FIG. 295G, the lastcannula inserted, such as third cannula 85108, may include a slidingtissue lock 85112 for coupling cannula 85108 to a patient's skin. Such atissue lock 85112 may be part of a cannula or, in alternativeembodiments, it may be a separate component slideable over a cannula.Such a sliding tissue lock 85112 may help stabilize a cannula 85108,since it would be attached to tissue inside the patient and locked atthe skin as well.

In various embodiments, the method described in FIGS. 295A-295G mayinclude any number of sliding cannulas, such as but not limited tobetween two and ten cannulas. Each cannula may be made of any suitablematerial or combination of materials, such as but not limited tostainless steel, Nitinol, other metal, polymer, ceramic or the like. Insome embodiments, cannulas 85100, 85104, 85108 may be used with a spinalaccess system such as the one described in FIG. 293. Once access isachieved, any suitable procedure may be performed, such as but notlimited to a minimally invasive spinal decompression procedure likethose described in patent applications incorporated previously byreference.

Referring now to FIG. 296, in an alternative embodiment, a tissuelocking cannula device 85114 may be inserted into a patient and attachedto periosteum of a vertebral bone, such as periosteum covering avertebral lamina. In such an embodiment, cannula device 85114 may beused to provide an access window 85116 through which a laminotomy may beperformed, thus providing access through a lamina to the epidural space.FIG. 296 illustrates a posterior view of two adjacent vertebrae with oneexample location for placement of cannula device 85114 and window 85116.In alternative embodiments, any number of other locations may be usedfor placement of device 85114. In one embodiment, a portion of device85114 may be placed over vertebral bone, attaching to periosteum, andportion may be placed over an intervertebral space, attaching toligamentum flavum.

With reference now to FIG. 297, in an alternative embodiment, a tissuelocking cannula 85120 and other access system components may be used toaccess a spine and pass a guidewire through a space between twovertebrae, through the epidural space, and back out of the spine througha space between two different vertebrae (or one of the first vertebraeand an adjacent vertebra). For example, in FIG. 297, locking cannula85120 is passed between the L1 and L2 vertebrae and attached toligamentum flavum LF tissue. A probe 85122 extends through cannula85120, a guide member 85124 extends through probe 85122, and a guidewire85126 extends through guide member 85124. Rather than extending into orthrough an intervertebral foramen IF, guide member 85124 passes into theepidural space, through ligamentum flavum LF and between the L2 and L3vertebrae. Guidewire 85126 thus passes into the spine between L1 and L2and out of the spine between L2 and L3. In one embodiment, guidewire85126 may then be used to advance a tissue removal device into the spineto remove tissue to treat central spinal stenosis.

Referring now to FIGS. 298A and 298B, in one embodiment, multiple tissuelocking cannula may be slideably coupled in a telescoping, tissuelocking cannula system 85130. In one embodiment, cannula system mayinclude multiple cannulae 85132, each having at least two tissue lockingbarbs 85133 at its distal end, and each having a small handle or stop85134 at its proximal end. In various embodiments, any number ofcannulae 85132 may be included, such as but not limited to between twoand ten cannulae, or as shown in FIGS. 298A and 298B, five cannulae85132. Each cannula 85132 may have any desired diameter, ranging forexample from between about 1 mm and about 30 mm in diameter, or morepreferably ranging from between about 1 mm and about 20 mm.

In any of the variations described herein, the barbs or anchors may beconfigured so that they do not completely penetrate the tissue. Forexample the barbs (or other anchoring members) may be configured so thatthey removeably attach. For example, the barbs may only shallowly attachto the ligamentum flavum, protecting the tissue (e.g., nerves, etc.)below the ligamentum flavum from potential damage by the anchoringmembers. For example, the barbs may be configured to penetrate less than2 mm, less than 1.5 mm, less than 1 mm, etc. into the ligamentum flavum.In some variations, the barbs are configured so that they are limitedfrom extending deeply. For example, the barbs may be shaped or angled sothat they only shallowly penetrate the tissue such as the ligamentumflavum.

In use, cannula system 85130 may be used in a spinal access methodsimilar to the one described in FIGS. 295A-295G. System 85130 may beadvanced into a patient in a configuration such as in FIG. 298A, with afirst, smallest diameter cannula 85132 a in a front (or most distal)position. First cannula 85132 a may be locked into (attached to) tissuesuch as ligamentum flavum by rotating a first handle 85134 a, and then asecond cannula 85132 b may be advanced over it and locked into thetissue by rotating a second handle 85134 b. Once second cannula 85132 bis locked to tissue, first cannula 85132 a may be released from thetissue by rotating it in an opposite direction from the lockingdirection and then withdrawing first cannula 85132 a from system 85130.Alternatively, first cannula 85132 a may be left in place and removedlater in the access process. Third 85132 c, fourth 85132 d and fifth85132 e cannulae may be advanced in succession in the same manner, witheach smaller cannula being removed when the next largest cannula isattached to tissue. Thus, a path into the patient's tissue and to thespine is gradually dilated, until a largest diameter cannula 85132 e isin place and attached to ligamentum flavum, periosteum and/or otherspinal tissue. Any of a number of procedures may then be performedthrough cannula 85132 e, such as but not limited to a spinaldecompression procedure and/or a spinal fusion.

FIG. 298B shows a configuration of telescoping, tissue locking cannula85130 in which the smaller cannulae 85132 a-85132 d have been partiallywithdrawn from the largest diameter cannula 85132 e. As mentioned above,in various embodiments, each cannula 85132 may be removed individuallywhen the next largest cannula has been placed, or alternatively allcannulae 85132 may be placed before removing the smaller cannulae.

Referring now to FIG. 299, in another embodiment, a tissue lockingcannula 85140 may include multiple tissue locking barbs 85144, as havebeen described previously, and at least one of a proximal port 85142 ora distal port 85143 for helping guide an epidural probe 85146 (orepidural needle) through cannula 85140 an into an epidural space. Asshown, cannula 85140 may be attached to tissue such as ligamentum flavumLF, and probe 85146 may be advanced through cannula 85140, with ports85142, 85143 helping to guide probe 85146 in a desired orientation. Inalternative embodiments, only proximal port 85142 or only distal port85143 may be included. Ports 85142, 85143 may be made of a flexiblematerial, such as a polymer, to create a structure similar to a flap, oralternatively they may be made of a rigid material such as a metal.

With reference to FIG. 300, in another embodiment, a tissue lockingcannula 85150 may be coupled with bone periosteum and may include a port85152 for guiding a needle 85154 or probe. In one embodiment, needle85154 (or probe) may include threads 85156 which fit with complementarythreads on port 85152, thus allowing needle 85154 to be threaded/screwedinto cannula 85150. Such threads 85156 may facilitate gradual,controlled advancement of needle 85154 into the epidural space. In someembodiments, as illustrated in FIG. 300, cannula 85150 may be attachedto periosteum of adjacent vertebral bones, such as the laminae ofadjacent vertebrae, and needle 85154 or probe may be advanced throughligamentum flavum LF into the epidural space. In alternativeembodiments, cannula 85150 may be attached to periosteum of one lamina,to ligamentum flavum LF, or to periosteum and ligamentum flavum LF.

Referring now to FIG. 301, in another embodiment, a tissue lockingspinal access cannula 85160 may include a proximal tubular portion 85162and a distal expandable portion 85164 including multiple tissue lockingbarbs 85166. Products such as the Atavi® Atraumaic Spine Surgery System(provided by Zimmer Holdings, Inc., Warsaw, Ind.) provide a cannula withan expanding distal portion but do not provide for locking with internalpatient tissue. Cannula 85160 combines the convenience of expandabledistal portion 85164 with tissue locking barbs 85166 to help stabilizethe device 85160 within the patient.

With reference now to FIGS. 302A and 302B, in one embodiment, a spinalaccess probe system 85170 may be configured for use through a minimallyinvasive access cannula, such as one or more of the cannulae describedabove and/or currently available cannulae, such as but not limited tothe Atavi® Atraumaic Spine Surgery System (referenced above) or theMedtronic METRx™ MicroDiscectomy System (Medtronic, Inc.,www.medtronic.com). In many cases, instruments to be used through such aminimally invasive cannula system may benefit from being curved orbayoneted, so a surgeon's view through the cannula will not be blockedby the instruments. Thus, in one embodiment, probe system 85170 mayinclude a curved (or “bayoneted”) probe 85172, including a proximal bend85174 and a distal bend 85176, as well as a handle 85178. A curved guidemember 85180, such as those described previously above, may slidethrough probe 85172 and may include a proximal handle 85182 and anatraumatic distal tip 85184. As shown in FIG. 302B, atruamatic tip 85184may include an aperture 85185. A guidewire 85186 may be passed throughguide member 85180 to pass out of aperture 85185, as has been describedpreviously. Also as described previously, the various components ofsystem 85170 may be made of any suitable material or combination ofmaterials, such as but not limited to stainless steel, Nitinol, othermetals, polymers and the like.

In addition to those described above, other spinal access devices,systems and methods are also described and illustrated below, and any ofthese devices and systems may be used with any of those described above.For example, any of the ligamentum flavum access tool devices describedherein may be used with one or more of the removeably attachable tissuelocking cannula.

For example, FIGS. 303A to 307D illustrate five variations of ligamentumflavum access tools and methods of using them to access a patient'sepidural space. Any of the features or elements of these exemplaryvariations may be used with any of the other exemplary variations.

In general, a ligamentum flavum access tool may atraumatically access apatient's epidural space. These devices may include an outer hypotube(i.e., cannula) member and an inner member that is axially movablerelative to the outer member. The inner (atraumatic) member typicallyextends distal to the outer member. In some variations the outer memberis sharpened. For example, the outer member may be a cannula having asharp or cutting edge. The inner member, the outer member or thecombination of the two may have an atraumatic tip (e.g., domed, blunt,mushroom-shaped, etc.). The device (and particularly the outer member)may be advanced in a controlled fashion, and is configured so that theuser does not axially advance the device towards the dura. For example,the device may be anchored (e.g., directly to the patient or to asurgical access platform) and advanced by a rotary (e.g., screwing)motion. For example, the device or a portion thereof may be threaded onan outer surface so that rotating the device in a first direction causesit to advance. In some variations, the device may be geared so that therate of advancing and/or retraction of the device towards the dura maybe even more finely controlled.

The device may also include one or more detectors for detecting when thedevice (or a portion of the device) has penetrated the ligamentumflavum. For example, the device may include a hole or opening in thedevice for detecting a loss of resistance once the device has penetratedthe ligamentum flavum.

FIGS. 303A-303H illustrate one variation of a ligamentum flavum accesstool, configured as a ligamentum flavum punch. FIG. 303A illustrate aperspective view of the ligamentum flavum access tool 851301 approachingthe ligamentum flavum 851300. For the sake of simplicity, this exampleshows the tool approaching without any additional guide. In use, thetool may be applied within a cannula or other guide. For example, theligamentum flavum access tool may be applied within a tissue lockingcannula that has been secured to the ligamentum flavum, as illustratedand described above (e.g., instead of a penetrating needle, the systemmay include a ligamentum flavum access tool used in any of the waysdescribed above). Thus, a cannula may be placed attached to (oradjacent) the ligamentum flavum and used to deliver the ligamentumflavum access tool. Alternatively, the ligamentum flavum access tool mayapproach the ligamentum flavum without the benefit of an additionalguide.

The ligamentum flavum access tool in FIG. 303A includes a distal blunthead region 851304 and a more proximal outer cannula 851306. A loss ofresistance detector is located on the proximal outer cannula 851306.

In this variation, the ligamentum flavum access tool includes anatraumatic leading tip 851304 that is similar to a mushroom head tominimize trauma to dura during penetration of ligamentum flavum (LF). Analternate tip design could match the profile of a Penfield 4, adissector with a thin-profile, atraumatic tip that is commonly used topenetrate the LF. Immediately proximal to the leading tip in thisexample, is a hypotube (proximal cannula) 851306 with a sharpened edgeand a distal side hole 851308 for loss of resistance detection once thedevice has penetrated the LF.

The entire assembly may be advanced through the LF and into the epiduralspace in a controlled fashion. For example, the ligamentum flavum accessdevice may be advanced using a screw thread system. In this variation,the device may be anchored to the patient (or to a surgical accessplatform). The user does not apply axial force (towards the dura) togain access to the epidural space. Instead, the distal tip is advancedwith a screw thread which provides a controlled and consistent movementof the tip through the LF. As the device is advanced, the atraumatic tipand sharpened hypotube move together as a single unit through the LF andinto the epidural space. Epidural access is detected through the sideport in the hypotube using the loss of resistance technique. This isillustrated in greater detail in FIGS. 303B and 303C (showing across-section through the device).

In this example, once epidural access has been achieved, as shown inFIG. 303D, the leading tip (e.g., a mushroom head or Penfield 4 profileor any other appropriate profile) is held fixed within the epiduralspace while the sharpened hypotube is retracted proximally and withdrawnto the exterior of the LF, as shown in FIG. 303E. In some variations,only the distal inner member is advanced while the proximal hypotuberemains outside of the ligamentum flavum. In such variations, it may beuseful to have the loss of resistance input (opening 851308) on thedistal head region.

Once the sharpened hypotube is completely outside of the LF, as shown inFIGS. 303E and 303F, the hypotube is rigidly fixed in this position. Asa result, the LF is sandwiched between the leading tip (proximalsurface) and the sharpened hypotube.

As shown in FIGS. 303E and 303H, the leading tip may be pulled backproximally towards the hypotube thereby tenting the LF and pushing itagainst the sharpened hypotube edge. In this way, a hole in the LF iscreated through this punching action. In addition, the plug of removedLF will be captured within the hypotube and not be lost within theepidural space.

Other variations of ligamentum flavum access tools are shownside-by-side in FIG. 303J. The variation shown on the far left 851391 isthe ligamentum flavum punch tool shown in FIGS. 303A-303H, in which thedistal end of the tool (the distal blunt head region) is configured as ablunt, essentially mushroom-shaped cross-section. The variation 851393shown in the middle of FIG. 303J has a slightly more tapered head851304′, which is bullet shaped. This variation is otherwise similar tothe variation illustrated in FIGS. 303A-303H, and may otherwise be usedthe same. Similarly, the variation shown in the far right 851395 of FIG.303J is even more steeply tapered, and has a conical or silo tip 851304″on the distal blunt head region. Any of the distal head regionsdescribed herein may be shaped as shown in FIG. 303J, or other similarblunt shapes.

Any of the ligamentum flavum access tools described herein may also beconfigured so that they have an asymmetric cutting shape. FIG. 303Killustrates one variation of a ligamentum flavum access device thatincludes an asymmetric cutting region. This example is similar to thevariations shown above (e.g., in FIGS. 303A-303J), and includes a distalhead region (blunt head region) that is configured to extend into theligamentum flavum. The head region in FIG. 303K also attaches to anelongate member (e.g., cannula, wire, rod, etc.), but attachesasymmetrically, so that, rather than a “mushroom shape” as shown, thedistal head has an opening more to one side of the device than theother. This allows the ligamentum flavum to extend beneath the head ofthe device as described above, e.g., in FIG. 303F, however it extendsasymmetrically. In this variation, and in similar variations, the cut inthe ligamentum flavum may not be round, but may have a profile that isoval, half-circle, crescent, or other shapes.

FIGS. 304A-304G illustrate the operation of another variation of aligamentum flavum access device. In this variation the access device isconfigured as a ligamentum flavum dilator.

FIG. 304A shows this variation of a ligamentum flavum access device851401 prior to penetrating the ligamentum flavum 851400. Thedistal-most member of this variation is configured as an atraumaticleading tip 851404 similar to mushroom head to minimize trauma to duraduring penetration of ligamentum flavum (LF). An alternate tip designwould closely match the profile of a blunt spherical shape. Proximal tothe end of the device, there is a distal side hole for loss ofresistance detection once the device has penetrated the LF. Immediatelyproximal to the leading tip is a hypotube 851406 with axial slits at thedistal tip.

As illustrated in FIGS. 304B and 304C, the entire assembly is advancedthrough the LF and into the epidural space, in a controlled fashion,e.g., using a screw thread system. The entire device may be anchored tothe patient (or to a surgical access platform). The user does not applyaxial force (towards the dura) to gain access to the epidural space.Instead, the distal tip is advanced with a screw thread which provides acontrolled and consistent movement of the tip through the LF. As thedevice is advanced, the atraumatic tip and slit hypotube may movetogether as a single unit through the LF and into the epidural space.Epidural access is detected through the side port in the leading tipusing the loss of resistance technique.

Any of the devices described herein may include a sensor to determineepidural access. In addition to the loss of resistance technique sensorsmentioned, other sensors (pressure, resistance, force, biomarker, etc.)may be used. In some variations the sensor may be electronic.

As shown in FIG. 304D, the entire device (assembly) may be inserteduntil the expandable distal region of the outer member is within theligamentum flavum. Once epidural access has been achieved, as shown inFIG. 304E, the leading tip (mushroom head or blunt, spherical shape) maybe retracted proximally while the slit hypotube is held fixed within theepidural space.

As shown in FIGS. 304F and (in cross section) 304G, the process ofpulling the blunted tip through the center of the slit hypotube causesthe distal end of the tube to flare open under the wedging action of thetube ID to tip interface. The flaring open of the distal end of thehypotube within the LF dilates the entry site and expands the opening inthe LF. This concept takes advantage of a small, atraumatic entrythrough the LF and subsequent dilation of this entry point to provideadequate access to the epidural space, as shown.

FIGS. 305A-305E illustrate another variation of a ligamentum flavumaccess device, configured as a vacuum device.

For example, FIG. 305A shows a side view of this variation. The distalend of device 851501 is comprised of 2 close-fitting, concentrichypotubes. The outer hypotube 851506 has a sharpened edge. The entireassembly may be advanced to the LF 851500 and be docked to the LF outersurface. The entire device can be anchored to the patient (or to asurgical access platform). Thus, as with the other variations described,the user does not apply axial force (towards the dura) to advance thedevice against the LF. Instead, the distal tip is advanced with a screwthread which provides a controlled and consistent movement of the tip tothe LF.

As shown in FIGS. 305B and (in cross section) in FIG. 305C, the deviceis advanced, and in this example the concentric hypotubes 851504, 851506move together as a single unit. Once contact with the LF is achieved,the axial position of the sharpened outer tube is held fixed.

Vacuum may then be drawn through the inner tube thereby drawing theouter surface of the LF to the inner tube, as shown in FIG. 305D. Withthe outer tube held fixed axially, the inner tube is drawn biasedproximally under the influence of a spring. In this way, the inner tubeis pulling the LF against the outer tube sharpened edge. With the LFpulled against the outer tube, the outer tube can be rotated in place.This rotation slices into the LF. As the LF is cut, the spring tensionon the inner tube draws the LF further into the outer tube to advancethe cutting depth into and eventually through the entire LF. Completionof cutting through the LF can be detected when the inner tube no longerencounters resistance against the proximally directed spring bias. Atthis point, a hole has been cut through the LF and epidural access hasbeen gained. This is illustrated in FIG. 305E.

FIGS. 306A-306D illustrate another variation of a ligamentum flavumaccess device, configured as a ligamentum flavum barb. In FIG. 306A theligamentum flavum access device 851601 includes an atraumatic leadingtip 851604 (which may be shaped similar to a mushroom head) to minimizetrauma to dura during penetration of ligamentum flavum (LF) 851600. Analternate tip design could match the profile of a Penfield 4, asdescribed above. In this variation, the proximal surface 851606 of theleading tip is a cutting edge, and may be barbed, serrated, or the liketo enable tearing or cutting of the of the ligamentum flavum.

A hypotube extends immediately proximal from the leading tip, and mayinclude a distal side hole for loss of resistance detection once thedevice has penetrated the ligamentum flavum. Alternatively, one or moreother sensors for determining when the device has penetrated into theepidural space may be used.

The entire assembly may be advanced through the ligamentum flavum, andinto the epidural space in a controlled fashion, as illustrated in FIG.306B. The device may be controllably advanced, as previously described.For example, the device may be advanced using a screw thread system. Theentire device may be anchored to the patient (or to a surgical accessplatform), so that the user does not apply axial force towards the durato gain access to the epidural space. Instead, the distal tip may beadvanced with a screw thread which provides a controlled and consistentmovement of the tip through the ligamentum flavum. As the ligamentumflavum access device is advanced through the ligamentum flavum, theligamentum flavum may be tented and stretched as the device passesthrough.

As the device is advanced, the atraumatic tip may be moved through theligamentum flavum 851600 and into the epidural space, as shown in FIG.306C. The head of the device may penetration into the epidural space sothat the proximal cutting surface is within the epidural space.Advancing the device may stop once the epidural space entry is detected.For example, epidural access may be detected through the side port inthe hypotube behind the leading tip using the loss of resistancetechnique. Once epidural access has been achieved, the leading tip(mushroom head or Penfield 4 profile) can be retracted proximally,engaging the barbs of the proximal cutting surface against the innersurface of the ligamentum flavum.

After the ligamentum flavum is engaged by the barbs, the device may bepulled in the proximal direction tearing a hole in the ligamentum flavumas it is withdrawn, as shown in FIG. 306D. In this way, an opening forepidural access has been created. The device may be rotated or moved toassist in cutting the ligamentum flavum.

FIG. 306E shows other variations of the ligamentum flavum barb-typeaccess devices, including the variation illustrated in FIGS. 306A-306D.The variation shown on the far left of FIG. 306E, 851691, is identicalto the variation illustrated in FIGS. 306A-306D. The variation of aligamentum flavum barb shown in the middle of FIG. 306E, 851693, has aconical or silo tip 851604′. Similarly, the variation shown in the farleft of FIG. 306E has a bullet shaped tip 851604″. Any of these devicesmay be used as illustrated and described above for FIGS. 306A-306D.

FIGS. 307A-307D illustrate another variation of a ligamentum flavumaccess device, configured to expand within the epidural space, andsupport the ligamentum flavum so that it can be cut. In this variationan inner member 851704 includes a distal atraumatic portion 851706 thatis configured as a rounded tip region 851718 that has at least onedetector for determining when the distal tip has accessed the epiduralspace. In the example shown in FIG. 307A, the distal tip 851718 has anopening 851716 for loss of resistance detection. An elongate neck regionextends from the distal tip 851718 of the epidural access device 851702,and includes a threaded region 851712 which may mate with a cuttingelement (e.g., a cannula including a cutting edge), as illustrated inFIG. 307C. The elongate neck region may then continue proximally 851714.

One or more extendable support elements are extendable from the distalportion 851718 of the inner member 851706 when the inner member iswithin the epidural space. For example, the inner member may include oneor more arms that extend from the distal region of the inner memberafter it has passed into the epidural space. In some variations thesupport element(s) are arms made of Nitinol or other shape-memory orappropriately deformable material that may be extended from the innermember (e.g., substantially perpendicular to the long axis of the innermember). FIG. 307B illustrates the extension of three support members.

In FIG. 307B, three support members 851721 are deployed from the distalend of the inner member 851702 by pushing an expandable inner memberfrom the lumen of the inner member. For example, a wire, pushrod, orother element 851722 may be used to deploy the extendable members fromthe distal end of the inner member. The deployable member(s) may also beretracted into the inner member by pulling up (e.g., on element 851722).As illustrated in FIG. 307B, the support elements 851721 may be expandedfrom the inner member in a direction that is substantially perpendicularfrom the inner member. For example, the exit openings on distal regionof the inner member may be oriented on the sides of the device. In somevariations the support member is pre-biased so that extendsapproximately perpendicularly from the inner member.

Thus, the support member(s) may be configured to extend into theepidural space without damaging nearby structures, and may extend underthe ligamentum flavum so that it can be supported during cutting. Insome variations the support members are atraumatic support members, andmay include non-sharp (e.g., rounded, etc.) distal ends or othersurfaces.

After deploying the support member(s) from the inner member 851702, anouter member 851701 may be applied to cut the ligamentum flavum, asillustrated in FIG. 307D. In this example, the outer member 851701 isconfigured as a hypotube (or cannula) having a cutting edge 851730. Theouter hypotube is located proximal to the inner member (and maytherefore be referred to as a proximal hypotube), and may be coupled tothe inner member so that it can be advanced once the inner member hasengaged the ligamentum flavum. For example, the outer member (proximalhypotube) may be threaded so that it can be advanced by rotating, andscrewed down over the ligamentum flavum, as shown in FIG. 307D. Thus, byclamping or compressing the outer and inner members, the portion of theligamentum flavum between them may be cut and removed. In FIG. 307D, theligamentum flavum access device, including the cut portion of theligamentum flavum, may then be removed. In this example, a 5-20 mmportion of the ligamentum flavum may be removed in this fashion. Evenafter removal of the ligamentum flavum access device, access into theepidural space may be secured. For example, the device may not beremoved until after a guide element (e.g., guidewire or the like) hasbeen positioned through the ligamentum flavum. In some variations, onlya portion of the epidural access device is removed. For example, theinner member may be removed, allowing access of other portions.

In still other variations, the opening through the ligamentum flavum maybe expanded (e.g., FIGS. 304A-304G), and the expander may be left inwhile positioning a guidewire or the like. In any of the ligamentumflavum access devices described herein, a cannula, such as a tissuelocking cannula, may be left in place for some time even after removalof all or a portion of the ligamentum flavum access device.

FIGS. 308A and 308B show one variation in which an access port, ananchoring cannula, is secured in the opening formed by the ligamentumflavum access device. For example, in FIG. 308A, after forming anopening through the ligamentum flavum, a cannula may be placed withinthe opening formed. The access cannula 851801 in this example is slidover the distal end of the ligamentum flavum access device 851803.Although in this example, the ligamentum flavum access device 851803shown is a variation including a support member similar to the deviceshown in FIG. 307A-307D, any of the ligamentum flavum access devicesdescribed herein may be used.

The access cannula in this example thus spans the opening through theligamentum flavum, and can be anchored in place using one or moreanchors 851805. For example, the access cannula may include one or morebarbs or members that either extend or are extendable outwards to engagetissue (including bone) and secure the cannula in place. As mentionedabove, the access cannula may also be configured as a tissue lockingcannula. In some variations, the distal end of the access cannulainclude one or more tissue-engaging surfaces.

An access cannula may also be referred to as a dilation tube 851801. Insome variations the dilation tube is configured to further expand theopening formed by the ligamentum flavum access device. For example, thedilation tube may include walls configured to expand outwards to enlargethe opening. As shown in FIG. 308B, once the access tube/dilationcannula is in position to access the epidural space and span theligamentum flavum (and may be anchored in place), the inner ligamentumflavum access device may be removed.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. These and many other modificationsmay be made to many of the described embodiments. Therefore, theforegoing description is provided primarily for exemplary purposes andshould not be interpreted to limit the scope of the invention as it isset forth in the claims.

Devices, Methods and Systems for Neural Localization

Many types of surgical intervention require manipulation of one or moremedical devices in close proximity to a nerve or nerves, and thereforerisk damage to the nerve tissue. For example, medical devices may beused to cut, extract, suture, coagulate, or otherwise manipulate tissueincluding or near neural tissue. It would therefore be beneficial toprecisely determine the location and/or orientation of neural tissuewhen performing a medical procedure.

Knowing the location or orientation of a nerve in relation to a medicaldevice (e.g., a probe, retractor, scalpel, etc.) would enable moreaccurate medical procedures, and may prevent unnecessary damage tonearby nerves. Although systems for monitoring neural tissue have beendescribed, these systems are relatively imprecise. Further, many ofthese systems require large current densities (which may also damagetissue) and may be severely limited in their ability to accurately guidesurgical procedures. For example, in many such systems a current isapplied from an electrode (e.g., a needle electrode) in order to evokean efferent muscular response such as a twitch or EMG response. Suchsystems typically broadcast, via the applied current, from the electrodeand the current passes through nearby tissue until it is sufficientlynear a nerve that the current density is adequate to depolarize thenerve.

Because the conductance of biological tissue may vary betweenindividuals, over time in the same individual, and within differenttissue regions of the same individual, it has been particularlydifficult to predictably regulate the applied current. Furthermore, thebroadcast fields generated by such systems are typically limited intheir ability to spatially resolve nerve location and/or orientationwith respect to the medical device.

For example, US patent application 2005/0075578 to Gharib et. al. and US2005/0182454 to Gharib et al. describe a system and related methods todetermine nerve proximity and nerve direction. Similarly, U.S. Pat. No.6,564,078 to Marino et al. describes a nerve surveillance cannula systemand US 2007/016097 to Farquhar et al. describes a system and method fordetermining nerve proximity and direction. These devices generally applyelectrical current to send current into the tissue and therebydepolarize nearby nerves. Although multiple electrodes may be used tostimulate the tissue, the devices, systems and methods described are donot substantially control the broadcast field. Thus, these systems maybe limited by the amount of current applied, and the region over whichthey can detect nerves.

Thus, it may be desirable to provide devices, systems and methods thatcontrollably produce precise electrical broadcast fields in order tostimulate adjacent neural tissue, while indirectly or directlymonitoring for neural stimulation (e.g. EMG, muscle movement, or SSEP),and thereby accurately determine if a nerve is in close proximity to aspecified region of the device.

Described herein are devices, systems and methods for determining if anerve is nearby a device or a region of a device. In general, a devicefor determining if a nerve is nearby a device includes an elongate bodyhaving an outer surface with one or more bipoles arranged on the outersurface. These bipoles may also be referred to as tight bipoles, andinclude a cathode and an anode that are spaced relatively close togetherto form a limited broadcast field. The broadcast field may be referredto as the bipole field, or the field formed by the excitation of thebipole pair. In general, the bipole filed is a controlled or “tight”broadcast field that extends from the bipole pair(s).

A device for determining if a nerve is nearby the device may be referredto as a nerve localization device, a localization device, or aneurostimulation device. The elongate body region of the device may bereferred to as a probe, although it should be understood that anyappropriate surgical or medical device may be configured as a device fordetermining if a nerve is nearby the device. Particular examples of suchdevices are described below. For example, FIG. 309A shows a genericdevice 901 configured as a nerve localization device that having anelongate body 905 that may be configured to determine if a nerve isnearby.

The outer surface of a device for determining if a nerve is nearby aregion of the device may have two or more regions. In some variations,each region includes two or more bipole pairs that are arranged todetect a nearby nerve. The regions may be arranged around or along theouter surface of the device. For example, the regions may becircumferential regions that divide the outer surface up along thecircumference. Examples of different regions are described below. Eachregion may include one or more bipole pairs, which may be used to detecta nearby nerve.

Returning to FIG. 1A, the elongate body 905 has an outer surface with ablunt (atraumatic) end. In general, the outer body of the device 905 maybe formed of any appropriate material, including polymeric materialssuch as PEBAX, PEEK or the like. Non-conducting and biocompatiblematerials may be particularly preferred. In FIG. 309A, a single bipolepair 907 is shown near the distal end of the device. FIG. 309Billustrates an approximation of the current lines for a dipole pair,including the cathode 908 and the anode 906. These current lines reflectthe dipole field to broadcast field for the dipole pair.

A tight bipole pair may have a very limited broadcast field, asreflected in FIG. 309C, which shows the bipole pair of FIG. 309B havingonly the major current line. In some variations the size of the anode906 and cathode 906 forming the bipole pair are relatively small,particularly (e.g., less than 5 mm2, less than 3 mm2, less than 2 mm2,less than 1 mm2), and the anode and cathode are positioned sufficientlynearby so that the majority of current passes between the anodes andcathodes. For example, the anode and cathode of a bipole pair may beseparated by less than 5 mm, less than 2 mm, less than 1 mm, etc.

The limited broadcast field may allow stimulation of only nerves thatare very near the bipole pair. This may enhance accuracy, and helpprevent or limit tissue damage, particularly at the low stimulation.

When a region of the outer surface of a device includes more than onebipole, the bipoles may be arranged as a bipole network. A bipolenetwork includes at least two bipoles that are formed by at least threeelectrodes (e.g., two anodes and a cathode or two cathodes and ananode). The bipole network is typically arranged so that all of thebipoles in the network are activated synchronously to create aneffectively continuous bipole field along the outer surface. Forexample, FIGS. 309D and 309E illustrates an example of an effectivelycontinuous bipole filed. In this example, the anodes and cathodesforming the bipolar network are arranged so that the current between thetwo electrodes forms a zigzag pattern. Bipole pairs are located adjacentto each other and share either an anode or a cathode. FIG. 309Fillustrates another example of a bipole network, in which adjacentbipole pairs do not share anode or cathodes. This bipole network alsoforms an effectively continuous bipole field along the outer surface ofthe device. Adjacent bipole pairs are positioned close to each other.

In some variation all of the cathodes forming a bipole network areelectrically connected to each other and all of the anodes forming abipole network are electrically connected. For example, the anodes ofthe bipole network may all be formed from a single anodal connector, andall of the cathodes of a bipole network may be formed from a singlecathodal connector. Alternatively, all of the cathodes of the bipolenetwork may be formed separately and connected distally on the device.For example, all of the cathodes may be wired to a single connector thatconnects to a power source or controller configured to energize thebipole network in a particular region.

A device may include multiple bipole networks. For example, differentregions on the surface of the device may include different bipolenetworks (e.g., each region may have its own bipole network). The bipolenetworks in different regions may be non-overlapping, and may formeffectively non-overlapping continuous bipole fields. “Effectivelynon-overlapping bipole fields” means that the broadcast fields of two ormore bipole networks do not substantially overlap. For example, thecomponent of a broadcast field (e.g., intensity) due to a second bipolenetwork is less than 15% (or 10%, or 8% or 5% or 1%) of the componentdue to a first bipole network at any position near the first bipolenetwork, particularly at the excitation ranges described herein.

A device for determining if a nerve is nearby may also include acontroller for controlling the application of energy to the bipoles. Inparticular, the application of energy to the bipoles may be coordinatedas described in the methods sections below, so that the activation of anerve can be correlated to a particular region of the surface of thedevice.

In some variations, the bipole or bipole networks are movable withrespect to the outer surface of the device. Moving the bipole (e.g.,rotating it a around the outer surface) may allow a bipole field (atight or narrow broadcast field) to be correlated with different regionsof the device. This is also described in greater detail below.

Nerve Localization Devices

FIG. 310A, illustrates the distal portion of one embodiment of a devicecapable of determining if a nerve is nearby. This exemplary device 9080is shown in partial cross-section. For clarity, FIG. 310A does not showthe bipoles, thus showing more clearly the structure of probe device9080. In this example, the device 9080 includes a rigid cannula 9082 (ortube or needle) and a curved, flexible guide 9084 that can slide throughcannula 9082. The guide 9084 may include a Nitinol core 9086 (or innertube) having a central lumen 9088 and an atraumatic, rounded tip 9087and may also include a sheath 9089 (or coating or cover) disposed overat least part of Nitinol core 9086. The sheath 9089 may comprise, in oneembodiment, a polymeric material such as PEBAX, PEEK or the like, or anyother suitable material, and may form an outer surface having differentregions. Core 9086 may be made of Nitinol or may alternatively be madeof one or more other substances, such as spring stainless steel or othermetals. Lumen 9088, in some embodiments, may be used to pass aguidewire.

FIG. 310B is a perspective view of a portion of the probe 9080 of FIG.310A, in which two electrically conductive members 9090 are visible. Onemember may be a cathodal conductor and one member may be an anodalconductor. A probe may include as many electrode pairs as desired, suchas eight, sixteen, thirty-two, etc. In this example, the probe may havea preformed, curved shape and may be made of at least one flexible,shape memory material, such as Nitinol. In this way, guide 9084 may bepassed through cannula 9082 in a relatively straight configuration andmay resume its preformed curved shape upon exiting a distal opening incannula 9082. This curved shape may facilitate passage of guide 9074around a curved anatomical surface, such as through an intervertebralforamen of a spine.

The exemplary device shown in FIGS. 310A-310D may include at least onebipole network, including a plurality of anodes and cathodes. In thisexample, anodes of a single bipole network are all formed from the sameanodal conductor, and the cathodes of the same anodal conductor are allformed from the same cathodal conductor. FIG. 310C illustrates this. InFIG. 310C a section of probe sheath 9089, including the outer surfaceregion, is shown in more detail. In one embodiment, sheath 9089, whichfits directly over at least a portion of Nitinol core 9086 (FIG. 310A),includes multiple, longitudinal lumen 9092, each of which may contain anelectrical conductor 9094 forming a plurality of electrodes (e.g.,anodes or cathodes). In some embodiments, conductors 9094 may beslideably disposed inside lumen 9092, while in other embodiments theymay be fixedly contained therein. Openings into the sheath 9089 form theplurality of cathodes and anodes. The openings may be pores, holes,ports, slits, grooves or the like. Each aperture 9096 may extend from anouter surface of sheath 9089 to one of conductor lumen 9092. As such,apertures 9096 may help direct current along paths from one electricalconductor (e.g., cathodal conductor) to the other electrical conductor(e.g., anodal conductor) forming the plurality of bipolar electrodepairs. In some embodiments the conductor 9094 may partially extendthrough and above of the aperture 9096 surface. This may be achieved bya conductor 9094 that has several bends enabling the apex of the bend toprotrude through the aperture 9096. Alternatively, the conductor 9094may have sections of its length near the aperture 9096 that have alarger diameter than other sections of conductor 9094. In a givenembodiment, any number of lumen 9092, electrical conductors 9094 andapertures 9096 forming anodes or cathodes may be used. In someembodiments, apertures 9096 may extend along a desired length of sheath9089 to approximate, for example, a length of an area to be treated by adevice or procedure.

FIG. 310D shows a section of sheath 9089 is shown in cross section,showing an electrical conductor 9094 comprising (i.e., a cathodalconductor) and a current directing aperture 9096 (i.e., forming acathode of a bipole). In some embodiments, some or all of apertures 9096may be filled with a conductive material 9097, such as a conductive gel,solid, matrix or the like. Conductive material 9097 may serve the dualpurpose of helping conduct electric current along a path and preventingnon-conductive substances from clogging apertures 9096.

The example shown in FIGS. 310C-310D has four circumferential regionsspaced around the circumference of the outer surface of the sheathregion of the device. In this example, each region includes a bipolenetwork formed by an anodal and cathodal conductor that is positioned inparallel. Thus, the bipole network (similar to that shown in FIGS. 309Dand 309E) extends along the length of each surface region of the device,and may form an effectively continuous bipolar field along the outersurface.

FIG. 311 illustrates a similar arrangement having four regions whicheach include electrical connectors within the elongate body that mayform the bipole network. For example, in FIG. 311, four pairs 90102 ofanodal and cathodal conductors are shown. The conductors of each pair90102 are close enough together that electric current is transmittedonly between electrodes formed by each pair 90102 a and not, forexample, between electrode pairs formed by other anodal or cathodalconductors 90102 b, 90102 c, 90102 d. In some embodiments, the anodalconductor and the cathodal conductor may be “switched” to change thedirection that current is passed between electrodes formed by the twoconductors. For example, one conductor of each pair 90102 may bedesignated as the transmission conductor (cathode), and the otherelectrode of the pair 90102 may be designated as the return electrode(anode). When one of the conductors forming the anode or cathode is setto ground, this ground may be isolated from the ground (e.g., an anodalconductor) in other regions of the device, which may help isolate thecurrent to the bipolar network in a single region of the device. Invarious embodiments, electrodes forming the bipole pair may be spaced atany suitable distance apart by spacing the electrical conductors formingthe electrodes of the bipole pair. For example, electrodes of each pairmay be spaced about 0.1 mm to about 2 mm apart, or about 0.25 mm toabout 1.5 mm apart, or about 0.5 mm to about 1.0 mm apart.

FIG. 312 shows another example of a cross-section through a devicehaving pairs 90112 of electrical conductors that may form a network ofbipole pairs on the surface of the device. In this example, the anodaland cathodal conductors are spaced farther apart. Farther spacedelectrode pairs 90112 may allow current to pass farther into tissue butmay also risk dispersing the current farther and potentially being lessaccurate. Depending on the specific use and desired characteristics ofthe device (e.g., sheath 90110), the bipole pairs formed may be spacedat any of a number of suitable distances from one another.

Alternative arrangements of bipole pairs formed from an anodal andcathodal conductor are shown in FIGS. 313A-315B. For example, FIG. 313Ais a side-view of a pair of bipole pairs that are formed by apertures90122, 90124 in the body of the device (sheath 90120) which exposeportions of the cathodal electrical conductor 90126 and portions of theanodal conductor 90128. Apertures forming the cathodes 90122 and anodes90124 are disposed along a length of sheath 90120 separated by adistance d. As shown in FIG. 313B, the electrical conductors (i.e.,cathodal conductor 90126 and anodal conductor 90128) are embedded in theelongate body and are spaced apart from each other about acircumferential distance s. In one embodiment, the distance d may begreater than the distance s, so that current is more likely to travelcircumferentially between positive and negative electrodes, rather thanlongitudinally along sheath 90120. As can be appreciated from FIGS. 314Aand 315A, current may be directed along any of a number of differentpaths in different embodiments of elongate body (sheath 90120), bychanging the separation distances of apertures 90122, 90124 providingaccess to the electrical conductors 90126, 90128.

For example, in FIGS. 314A and 314B, the cathodal and anodal conductorsare positioned in immediately above and below one another, and aperturesforming the anodes and cathodes of bipole pairs may be spaced atdifferent distances along the body of the device 90130, such thatcurrent is more likely to travel between two closer spaced apertures(distance d′) than between two farther spaced apertures (distance d).

In FIGS. 315A and 315B, current may be directed along a distance dbetween apertures forming anodes and cathodes of bipole pairs that arespaced more closely together than the anodal and cathodal conductors ofother bipole pairs. As mentioned above, in various embodiments of thesenerve localization devices, any combination of anodal or cathodalconductors, apertures forming the anode and cathode pairs, and/or othercurrent direction path features may be included.

FIG. 316 shows a portion of a nerve localization device 90150. Thisnerve localization device variant includes a sheath 90152 havingmultiple current directing apertures 90154 disposed over a cathodalconductor and an anodal conductor, forming bipole pairs along the outersurface of the device. As shown, current may be driven along multiplepaths between pairs of apertures 90154 a, 90154 b, 90154 c, 90154 d.Multiple individual currents I1, I2, I3 and I4 add up to the totalcurrent IT transmitted between the anodal and cathodal conductor. Invarious embodiments, the bipole pairs formed 90154 may be disposed alongany desired length of probe 90150. Any number of bipole pairs may beincluded. As mentioned above, in some variations the cathodes and/oranodes formed in a single region of the device may be formed frommultiple (including individual) anodal/cathodal conductors (e.g.,wires).

FIG. 317 is a circuit diagram 90160 for a nerve localization devicehaving two bipole pairs (e.g., eight electrical conductors). In thissimple form, electric current may be driven between the electricalconductors along a top, bottom, left and right side, separately. Each ofthese side forms a different region of the device.

Another example of a nerve localization device is shown in FIG. 318. InFIG. 318, the nerve localization device includes two electricalconductors 90172, 90174 forming at least one bipole pair (not shown) andtwo rotating brushes 90176, 90178. Such an embodiment may allowdifferent sides, such as top, bottom, left and/or right sides, to bestimulated with only two electrodes 90172, 90174, rather than multipleelectrode pairs in different sections.

The elongate bodies forming part of the nerve localization devicesdescribed above may be used with any appropriate controller and/orstimulator configured to energize the bipole pairs. Thus, any of thesedevices may be used as part of a system including a controller and/orstimulator. In some variations, the elongate body may also be referredto as a probe. Examples of elongate bodies, including elongate bodieshaving different regions which may each contain one or more bipolepairs, are shown in FIGS. 319A-321D.

FIG. 319A is a simplified diagram of one variation of a device 9010.This device 9010 may be used to perform one or more medical procedureswhen orientation of the device with respect to an adjacent nerve isdesired. Similar to the device shown in FIG. 310A above, this variation9010 includes a cannula 9020 and a probe 9030. The device 9030 includesa tip 9040, a top section 9032, and a bottom section 9034. The device9030 may include multiple bipole pairs 9076, 9078 or bipole networksconsisting of multiple bipole pairs. A first bipole pair or bipolenetwork 9076 may be located on a first section 9032 and a second bipolepair 9078 may be located on a second section 9034. In one variation thebipole network or pair 9076 may be energized to determine whether anerve is located near or adjacent to the first or top section 9032. Thesecond bipole network or pair 9078 may be energized to determine whethera nerve is located near or adjacent to the second or bottom section9034. The first bipole network or pair 9076 and the second bipolenetwork or pair 9078 may be alternatively energized to independentlydetermine whether a nerve is located near or adjacent to the firstsection 9032 and/or the second section 9034.

In some variations a bipole pair or network 9076, 9078 is typicallyenergized with one or more electrical signal(s). The device may monitorthe electrical signal applied to the bipole network (or pair) 9076,9078, and may monitor the characteristics of the electrical signal anddetermine whether tissue is near or adjacent the bipole(s) 9076, 9078 asa function of the monitored electrical signal characteristics. Theelectrical signal characteristics may include amplitude, phase,impedance, capacitance, and inductance over time or frequency.

After an electrical signal is applied to the bipole network or pair9076, 9078, an output may be detected. In some variations the nervelocalization device includes a sensor or sensors for monitoring thenerve response. For example, the device may monitor one or more sensorsanatomically coupled to nerve or afferent tissue enervated by the nervewhose condition is modified by the signal(s) applied to the bipolarnetwork or pair 9076, 9078. For example, the device may monitor one ormore sensors innervated by the nerve tissue such as limb muscles.

The nerve localization devices and systems described herein may includeone or more indicators or outputs 9022, 9024. The detectors may providea user-identifiable signal to indicate the location of the nerve or thestatus of the system. For example, the nerve localization devices mayinclude one or more light emitting diodes (LEDs), buzzers (or othersound output), a video display, or the like. An LED may be illuminatedbased on signals generated by, received by, or generated in response tothe energized bipole(s) 9076 or 9078 as discussed above. In somevariations the system or devices create a vibration or sound that a usermanipulating the device 9020 may feel or hear. The intensity of theoutput may vary as a function of detected signal.

As shown in FIG. 319B, a nerve localization device may include a pair ofelectrical conductors 9036 (anodal conductor and cathodal conductor)which form one or more bipole pairs. The anode or a cathode of thebipole pair(s) 9076, 9078 may be formed as described above via anopening 9037 filled with a conductive material 9038, such as aconductive gel, solid, matrix, or other conductive material. An exampleof this is shown in FIG. 319C. Alternatively, the bipole pair 9036 andthe conductive material 9038 could be formed from the same conductiveelastic or semi-elastic material. The elongate body of the device 9030may include a bipole network comprising bipole pairs that are configuredin a coil or zig-zag pattern along the length of the probe. Thisarrangement may help ensure continuous conduction during flexion of theprobe 9030. In another variation, the anodal and/or cathodal conductorsare formed of conductive ink (e.g., loaded in an elastomeric matrix) maybe deposited on the outside of the probe. The conductive ink could beinsulated with the exception of discrete points forming the anode orcathode of the bipole pair. In another embodiment a thin flex circuitcould be wrapped around probe to construct the bipoles.

FIG. 319D is a partial, simplified diagram of one variation of a rongeurjaw 90680 configured as a nerve localization device. In this variationthe rongeur jaw forms the elongate body of the device on which at leastone bipole pair is located. The rongeur jaw 90680 may include a lowerjaw 90682 and an upper jaw 90684. The lower jaw 90682 may have a tip90688 and a bipolar network or pair 9078 on an inner surface. The upperjaw 90684 may have a tip 90686 and a bipolar network or pair 9076 on aninner surface. In one variation, the first bipolar network or pair 9078may be energized to determine whether a nerve is located near oradjacent to the first or bottom jaw 90682. The second bipole network orpair 9076 may be energized to determine whether a nerve is located nearor adjacent to the second or top jaw 90684. The first bipolar network orpair 9076 and the second bipolar network or pair 9078 may bealternatively energized to independently determine whether a nerve islocated near or adjacent to the first, bottom jaw 90682 and/or thesecond, upper jaw 90684.

In operation, a user may employ such a device to ensure that a nerve islocated between the lower jaw 90682 and upper jaw 90684 or that a nerveis not located between the lower jaw 90682 and upper jaw 90684. A usermay then engage the rongeur jaws 90680 to excise tissue located betweenthe jaws 90682, 90684. A user may continue to energize or alternatelyenergize the bipole networks or pairs 9076, 9078 on either jaw whileexcising tissue.

FIGS. 320A-320C are examples of elongate bodies having regions whichinclude at least one bipole pair, and may include a bipole network. Eachelongate body in FIGS. 320A-320C (9040, 9050, and 9060, respectively)may be part of a device or system capable of determining if a nerve isnearby the device, and may be configured as part of surgical instrumentsuch as a rongeur 90680, or other instrument. The configuration 9040shown in FIG. 320A includes two longitudinal regions 9042, 9044 at thedistal end. The distal section 9042 has a longitudinal length L1 and awidth R, which may also be referred to as a radial length. The moreproximal section 9044 has a longitudinal length L2 and a width of R.Each region 9042, 9044 includes at least one bipole pair 9046, 9048. Abipole pair 9046, 9048 typically includes at least one anode (−) andcathode (+) that can be excited to create a restricted current pathwaybetween the anode and cathode 9046, 9048.

The distance between the anode and cathode pair of may be less than thedistance between any of the electrodes forming part of a bipole pair inan adjacent region of the elongate body. For example, the electrodesforming the bipole pair (or bipole network) in the first region 9042 arecloser to each other than to either the anode or the cathode in theadjacent region 9044. Likewise, the distance between the anode andcathode pair in the second region 9044 is less than the distance betweenthe anode and the cathode of the first region. For example, the distancebetween the anode and cathode forming bipole pairs in the first region9042 is labeled D1 and the distance between the anode and cathode in thebipole pair in the second region is labeled D2. D1 may be less than orequal to L1 and R and D2 may be less than or equal to L2 and R. Anyappropriate spacing (D1 or D2) may be used between the anodes andcathodes forming the bipole pairs. For example, D1 and D2 may be about0.25 mm to 2.0 mm apart. In one variation D1 and/or D2 are about 0.50mm. When a bipole or bipole network in a region 9046, 9048, isenergized, current may flow between the anode and cathode along aconductive pathway substantially only within its respective sections9042, 9044. This current flow (and/or the related magnetic field) may bereferred to as the ‘broadcast field of the bipole pair or bipolarnetwork. A device including regions having tight bipoles or bipolenetworks 9040 may be employed to determine whether a nerve is closer tothe first region 9042 or the second 9044, as described above. The bipolepairs (or bipole networks) in each region may be alternatively energizedand an external sensor(s) can be used to monitor and/or determinewhether a nerve is closer to the first region 9042 or second region9044.

The arrangement of the bipole pairs or bipole network may help determinethe sensitivity of the device. For example, D1 may be less than D2,resulting in the bipole pair in the first region having a smallerbroadcast field (and a shorter conductive pathway) than the bipole pair9048 in the second region. This may allow detection of a nerve locatedfurther from second region than the first region, assuming a nearlyequivalent energy is applied to the bipole pairs (or networks) withineach region. Of course, the energy applied may be varied betweendifferent regions.

FIG. 320B shows an example of an elongate member 9050 having two regions9052, 9054 separated along the longitudinal (or circumferential if themember is rounded) axis of the member 9050. Each region 9052, 9054 mayinclude one or more a bipole pairs 9056, 9058. For example, each regionmay include a bipole network formed of multiple bipole pairs. Theindividual bipole pairs may share anodes and cathodes, as describedabove. In this example, the width of the first region is thecircumferential or linear distance, R1, and the length is the distanceL. The width of the second region is R2 and the length is L. The bipolepairs 9056, 9058 in each region may be longitudinally oriented, radiallyoriented, or some combination. For example, a bipole network may haveanodes and cathodes arranged in a linear pattern (e.g., extendinglongitudinally) or a zigzag pattern (also extending generally lineally).Other arrangements are possible.

FIG. 320C shows another variation of an elongate member having threeregions, two arranged longitudinally 9062, 9064, and one more proximally9063, adjacent to the two distal longitudinal (or circumferential)regions. Each region 9062, 9063, 9064 may include one or more bipoles9066, 9067, 9068 or bipole networks. The spacing between the electrodesforming the bipoles of a bipole pair or network in one of the regionsmay be less than the spacing to electrodes outside of the region. Thismay prevent current from passing from an electrode (e.g., anode,cathode) in one region and electrodes in another region. In somevariations the controller or device is configured so that the anodesand/or cathodes are electrically isolated (e.g., do not share a commonground) and may be configured to electrically float when not beingenergized.

FIGS. 321A-321D show partial cross-sections through elongate members90470, 90480, 90490, 90510 which may be used as part of a device fordetermining if a nerve is nearby. Each region includes multiple (e.g.,two or more) regions that each include one or more bipole pairs (e.g.,bipole networks). These examples each have a different cross-sectionalshape, and have circumferential regions that are oriented differentlyaround the perimeter of the elongate member. For example, FIG. 321Ashows a portion of a device having an outer surface that includes tworegions or sections 90472, 90474 that are circumferentially distributed.Each region 90472, 90474 includes one or more bipoles 90476, 90478,having at least one anode (−) and one cathode (+) that can be powered sothat current flows between the anode and cathode, resulting in abroadcast field. In this embodiment, the distances between the anode andcathode pairs forming the bipoles in each region are less than thedistance between the anode of one region and the cathode of the otherregion. Region 90472 may have a radial length R1 and circumferentialspan of L (e.g., a width of R1*pi); the longitudinal distance or lengthis not apparent from this cross-section, but may extend for somedistance. In this example, a bipole pair in the first region may have ananode and cathode 90476 that are separated by a distance (approximatelyD1) that is less than half the length of the first circumferentialregion, and the spacing of the tight bipole pair (approximately D2) inthe second region may be less than half the length of the secondcircumferential region. In one variation, D1 and/or D2 may be about 0.50mm. In some variations the spacing between the bipole pairs in differentregions (and within the same region for bipole networks) isapproximately the same.

The configuration 90480 shown in FIG. 321B may also include twocircumferential regions 90482, 90484 on the distal end of the elongatemember. Each region 90482, 90484 may include a bipole pair or network9086, 9088, as described above. In this embodiment, the distancesbetween the anode and cathode pairs of either of region 90486 and 90488are less than the distance between the anode of one region and thecathode of the other region.

The configuration 90490 shown in FIG. 321C includes four radial regions90492, 90494, 90502, 90504 which may also each have one or more bipole90496, 90498, 90506, 90508. FIG. 321D has two circumferential regions90512, 90514. Each radial region 90512, 90514 includes at least onebipole pair 90516, 90518.

FIGS. 322A-322C are partial diagrams of a portion of a device capable ofdetermining if a nerve is nearby. The device includes an elongate body(shown in cross-section) having to regions with at least one bipole pairin each region. The device is deployed in tissue 90522, 90524. Thedevice 90470 shown in FIG. 322A includes two radially separated regions90472, 90474, similar to the device shown in FIG. 321A. Each region90472, 90474 has a bipole network or at least one bipole pair 90476,90478 having an anode (−) and cathode (+). The device may determinewhether the module 90476 is near or adjacent a nerve (e.g., in thetissue 90522 or 90524) as a function of signals generated in response toone or more energized bipole pairs in the regions, as described above.When a bipole pair or network 90476 is energized, the conductive pathway(or bipole field) typically does not extend substantially into thetissue 90524, 90522.

The first region 90472 may have a radial length R1 and longitudinallength, L, and the second region 90474 may have a radial length R2 andlongitudinal length, L. An anode and a cathode forming at least onebipole pair within the first region 90472 may be separated by adistance, D1, and an anode and cathode in the second region may beseparated by a distance D2. In some variations the energy applied to abipole pair or network does not project very far into the tissue. Thismay be a function of the configuration of the bipole pair (e.g., thesize and spacing) and the energy applied. For example, the energyprojecting in to the tissue from a bipole pair in the first region 90472may not extend substantially further than a distance of T1, so that itwould not provoke a response from a neuron located further than T1 fromthe electrodes. Similarly, the energy projecting into the tissue from abipole pair (or the bipole network) in the second region 90474 may notextend substantially further than a distance of T2 from the electrodes.The electrodes of the bipole pair or network in the first region 90472may be are separated by a distance, D1 that is less than or equal to R1,T1, and L, and the bipole pair or network in the second region 90474 maybe separated by a distance D2 that is less than or equal to R2, T2, andL. For example, D1 and D2 may be about 0.25 mm to 2.0 mm apart (e.g.,0.50 mm). The energy applied to the bipole pair or network may belimited to limit the projection of energy into the tissue. For example,the current between the bipole pairs may be between about 0.1 mA to 10mA.

The device may be used to determine if a nerve is near one or moreregions of the outer surface of the device, and/or which region thenerve is closest to. For example, a first electrical signal may beapplied to the bipole pair/network in the first region 90472 for a firstpredetermined time interval, and a response (or lack of response)determined. A response may be determined by using one or more sensors,it may be determined by observing the subject (e.g., for muscle twitch),or the like. Thereafter a second electrical signal may be applied to thebipole pair/network in the second region 90474 for a secondpredetermined time interval, and a response (or lack of a response)determined. The first predetermined time interval and the secondpredetermined time interval may not substantially overlap, allowingtemporal distinction between the responses to different regions. Thedevice may include more than two regions, and the bipole network may beof any appropriate size or length.

Based on the monitored response generated after the application ofenergy during the predetermined time intervals, it may be determined ifa nerve is nearby one or the regions of the device, or which region isclosest. For example, if application of energy to the bipolepairs/networks in both regions results in a response, the magnitude ofthe response may be used to determine which region is closest. Thedurations of the predetermined time intervals may be the same, or theymay be different. For example, the duration of the first predeterminedtime interval may be longer than the duration of the secondpredetermined time interval. The average magnitude of the electricalsignals applied may be the same, or they may be different. For example,the magnitude of the signal applied to the bipole pair/network in thefirst region may be greater than the average magnitude of the signalapplied to the second region.

The device 90450 shown in FIGS. 322A and 322B includes twolongitudinally separated sections 90452, 90454. Each section 90452,90454 has a bipole pair or bipole network 90456, 90458 that has at leastone anode (−) and one cathode (+).

The device 90440 shown in FIG. 322C includes two longitudinallyseparated regions 90442, 90444, each including a bipole pair or network90446, 90448 including at least one anode (−) and one cathode (+). Whenthe bipole pair or network in a region is energized, the device may beused to determine if a nerve is nearby based on the generated responseto the energized bipole pair/network.

FIG. 322D shows a cross-section through a region of an elongate body ofa device having four regions which each include bipole pairs ornetworks. The electrodes forming the bipole pairs or networks areconnected to an electrically conductive element so that the anode(s) andcathode(s) in a particularly region are all in electrical communication.For example, as illustrated in FIG. 322D, four cathodal conductors90644, 90664, 90632, 90652 pass through the body of the device andelectrically connect to electrode regions (not visible in FIG. 322D) onthe surface of the device. Similarly, four anodal conductors 90642,90662, 90634, 90654 pass through the body of the device and electricallyconnect to electrode regions (not visible in FIG. 322D) on the surface.This forms bipole pairs 90640, 90660, 90630, 90650. When the cathodaland/or anodal conductors form multiple electrode regions (electrodes) ineach region, they may form a bipole network 90640, 90660, 90630, 90650.

FIG. 322E is a partial isometric diagram of a device shown in FIG. 322D,in which each region includes a bipole network formed along the lengthsof the device. Each bipole network includes anodes formed from a singleanodal conductor and cathodes formed from a single cathodal conductor.FIG. 322F is an exemplary illustration of an anode or cathode 90632. Theanode may have any appropriate shape (e.g., round, oval, square,rectangular, etc.), and any appropriate surface area (e.g., less than 10mm2, less than 5 mm2, less than 3 mm2, less than 2 mm2, less than 1mm2). For example, in some variations, the height of the anode orcathode (e.g., Y1) may be about 0.25 mm to 0.75 mm, and the width of theanode or cathode (e.g., X1) is about 3× the height (e.g., X1=3*Y1). Asmentioned previously, the electrode may be formed of a conductivematerial (e.g., metal, polymer, etc.), and may be formed by forming apassage into the body of the elongate member until contacting theconductive member, then filling the passage with an electricallyconductive material.

The conductive element may be a conductive wire, gel, liquid, etc. thatmay communicate energy to the anodes or cathodes.

The elongate body may be any appropriate dimension, and may be typicallyfairly small in cross-sectional area, to minimize the damage to tissue.For example, the outer diameter of elongate member may be about 1.5 mmto 5 mm (e.g., about 2 mm).

FIG. 323 illustrates conductive pathways 90550 of one example of adevice 90490 (similar to the variation shown in FIG. 321C) that includesfour radial regions 90492, 90494, 90502, 90504 near the distal region ofthe elongate body. Each bipole pair or network 90496, 90498, 90506,90508 includes at least one anode (−) and cathode (+) that, whenenergized, creates a limited conductive pathway between the respectiveanode(s) and cathode(s) of the bipole or bipole network 90496, 90498,90506, 90508. For example, the current pathways 90554, 90556, 90552, and90558 between the bipoles may broadcast energy about 3 to 5 times thedistance between the respective cathodes and anodes forming thebipole(s). Thus, the current pathways 90554, 90556, 90558, 90552 may besubstantially confined to the respective regions 90492, 90494, 90502,90504 of the elongate body forming the bipole or bipole network.

In operation, each bipole network is stimulated separately for apredetermined time. For example, one bipole network 90496, 90498, 90506,or 90508 may be energized with a first signal for a predetermined firsttime interval. Thereafter, another bipole network 90496, 90498, 90506,or 90508 may be energized with a second signal for a predeterminedsecond time interval. Different energy levels may be applied, forexample, as a function of the tissue 90522, 90524 that a user isattempting to locate or identify.

FIGS. 324A-324D are diagrams of electrical signal waveforms 90580,90590, 90210, 90220, 90230, 90240 that may be applied to one or morebipole pairs (or bipole networks). Exemplary signal waveforms includesquare-wave pulses 90582, 90584, 90586. Each pulse 90582, 90584, 90586may a have a similar magnitude and envelope. The square-wave pulses maybe idealized (e.g., with square edges, etc.), or rounded (as shown inFIGS. 324A-324D). The waveforms may be used to energize the bipolenetwork periodically P1 for a predetermined interval T1 where each pulse90582, 90584, 90586 has an amplitude A1. For example, A1 may be about0.1 milliamperes (mA) to 10 mA, the pulse width T1 may be about 100microseconds (μs) to 500 μs and the period P1 may from 100 ms to 500 ms.For example, A1 may be about 0.5 milliamperes (mA) to 5 mA, the pulsewidth T1 may be about 200 microsecond (μs) and the period P1 may about250 ms as a function of the energy required to depolarize neutraltissue. The applied energy may also be expressed as a voltage.

FIG. 324B illustrates another variation, in which the applied signalwaveform 90590 includes square-wave pulses 90592, 90594, 90596 that havean increasing magnitude but similar pulse width T1. The waveform 90590may be used to energize a bipole network periodically P1 for apredetermined interval T1 where pulses 90592, 90594, 90596 haveincreasing or ramping amplitudes A1, A2, A3. The waveform 90590 maycontinue to increase pulse amplitudes in order to identify a nerve (upto some predetermined limit). For example, stimulation of one or morebipole pairs may cycle a ramping stimulation. In one example, A1, A2,and A3 are about 1 milliamps (mA) to 5 mA where A3>A2>A1, the pulsewidth T1 may be about 100 microsecond (μs) to 500 μs and the period P1may from 100 ms to 500 ms. For example, the pulse width T1 may be about200 microseconds (μs) and the period P1 may about 250 ms.

In FIG. 324C the signals applied to energize different regions of thedevice are different. For example, a first waveform 90210 may be appliedto a first bipole network of a device, and a second waveform 90220 maybe applied to energize a second bipole network of the device. In thisexample, the signals are interleaved. The signal waveform 90210 includesseveral square-wave pulses 90212, 90214, and 90216 and the signalwaveform 90220 includes several square-wave pulses 90222, 90224, and90226. Each pulse 90212, 90214, 90216, 90222, 90224, 90226 may a have asimilar magnitude and envelope. The waveform 90210 may be used toenergize the first bipole network periodically P1 for a predeterminedinterval T1, where each pulse 90212, 90214, 90216 has an amplitude A1.The second waveform 90220 may be used to energize a second bipolenetwork periodically P2 for a predetermined interval T2 where each pulse90222, 90224, 90226 has an amplitude B1. In some variations, the pulsewidth T1, T2 is about 100 microseconds (μs) to 500 μs, and the periodP1, P2 is from 100 ms to 500 ms. For example, A1, A2 may be about 0.5milliamperes (mA) to 5 mA, the pulse width T1, T2 may be about 200microsecond (μs) and the period P1, P2 may about 250 ms. The pulses90212, 90214, 90216 do not substantially overlap the pulses 90222,90224, 90226. In some variations, T1>T2 and P2 is an integer multiple ofP1.

FIG. 324D is another example, in which different regions of the deviceare energized with pulses having increasing amplitudes. In this example,an amplitude increasing or ramping pulse waveform 90230 may be appliedto a first bipole network, and a second amplitude increasing or rampingpulse waveform 90240 may be applied to a second bipole network. Thesignal waveform 90230 includes several amplitude increasing or rampingsquare-wave pulses 90232, 90234, and 90236 and the signal waveform 90240includes several amplitude increasing or ramping square-wave pulses90242, 90244, and 90246. In variations having more than two regions,each region may be stimulated separately, so that the time periodbetween stimulations (P1-T1) may be larger than illustrated here.Methods may also include changing the stimulation applied, or scaling itbased on a response, as described in more detail below.

FIG. 325A is illustrates a schematic of a subject 90310 in which thedevice for determining if a nerve is nearby is being used. In thisillustration 90300, a tissue localization device 9010 is used as part ofa system including sensors 90322, 90324. In this system, the device 9010may energize one or more bipole pairs or bipole networks to depolarizeneutral tissue that is near a region of the device including the bipolepair or network. A sensor 90322 may be placed on, near, or within musclethat may be innervated when neutral tissue is depolarized by a nearbyenergized bipolar or optical module. The sensor 90322 may be innervatelycoupled to nerve tissue via a neural pathway 90316 and sensor 90324 maybe innervately coupled to nerve tissue via a neural pathway 90314. Forexample, the device may be used as part of a spinal procedure and thesensors 90322 may detect an Electromyography (EMG) evoked potentialscommunicated in part by a patient's cauda equina along the pathways90314, 90316.

FIGS. 325B-319D are simplified diagrams of sensors 90330, 90340, 90350that may be employed according to various embodiments. For example, asensor 90330 may include a multiple axis accelerometer employed on ornear muscle, particularly muscle innervated by neurons within the regionof tissue being operated on. The accelerometer may be a low-g triaxialaccelerometer. The accelerometer 90330 may detect differentialcapacitance where acceleration may cause displacement of the siliconstructure of the accelerometer and change its capacitance. The sensor90340 may include a strain gauge that also may be applied on or nearmuscle innervated by neurons within the region begin operated on. Thestrain gauge may a multiple planar strain gauge where the gauge'sresistance or capacitance varies as a function of gauge flex forces inmultiple directions. The sensor 90350 may include an EMG probe. The EMGprobe may include a needle to be inserted near or within muscleinnervated by a neuron or neurons within the region being operated on.For example, a sensor may determine a positive response when detectingan EMG signal of about 10 to 20 μV on the EMG probe 90350 for about 1second.

FIGS. 326A-326B illustrate the outer surface of a device having anelongate body having two regions 90446, 90448, wherein each regionincludes at least one bipole pair. The bipole pairs in the differentregions may have different geometries. For example the bipole pair inthe second region 90444 is spaced further apart (D2>D1) than the bipolepair in the first region 90442. This may result in the bipole pair inthe second region projecting the bipole field further into the tissuethan the bipole pair in the first region.

The configuration shown in FIG. 326B is similar, but illustrates abipole network 90449 in the second region 90444 that is a tripolarelectrode, having two anodes (−) separated from the cathode (+) in thisexample by different distances D2, D3. A bipole network may includeadditional cathodes and electrodes that are typically electricallycoupled (e.g., to the same anodal or cathodal conductor) so that theycan be stimulated substantially simultaneously.

Methods of Operation

In general, a method of determining if a nerve is nearby a device, or aregion of a device, includes the steps of exciting a bipole pair or abipole network to pass current between the bipole pair, resulting in alimited broadcast field that can stimulate a nearby neuron. Thebroadcast field may be limited by the geometry of the tight bipole pairsand the bipole networks described herein, and by the applied energy. Itcan then be determined if a nerve has been stimulated in response to theexcitation of bipole pair or network; the magnitude of the response canalso be compared for different bipole networks (or bipole pairs) indifferent regions of the device to determine which region is nearest thenerve.

FIGS. 327A-327C are flow diagrams illustrating methods of determining ifa nerve is near a device as described herein. In the algorithm 90380shown in FIG. 327A a first bipole network (or bipole pair) located on afirst region or section of a device having two or more regions isenergized 90382. The bipole network may be energized by the applicationof signal for a predetermined time interval. The energization of thebipolar module may generate a current between an anode (−) and cathode(+) (or anodes and cathodes). The subject is then monitored to determineif a response is detected 90384. If a response is detected, then a nervemay be nearby. The first bipole network may be energized with a firstsignal for a first predetermined time interval. In some variations, thefirst bipole network is energized as the device is moved within thetissue (e.g., as it is advanced) to continuously sense if a nerve isnearby. For example, FIG. 327B illustrates one method of sensing asadvancing.

In FIG. 327B the bipole pair in the first region is energized and aresponse (or lack of a response) is determined. The bipole network (orpair) may be energized as described above. For example, a continuoussignal may be applied, a periodic signal may be applied, or a varying(e.g., ramping) signal may be applied 90392. A response may be detectedby muscle twitch, nerve firing, or otherwise 90394. The device can thenbe moved based on the response 90396, or continued to be moved based onthe response. Movement may be continued in the same direction (e.g., ifno response is detected) or in a new direction (if a nerve is detected).Movement may also be stopped if a nerve is detected. Steps 90394 and90396 may b repeated during motion to guide the device.

In some variations, multiple regions of the device are stimulated todetermine if a nerve is nearby. For example, FIG. 327C illustrates onevariation in which a second region of the device, having its own,separated bipole network, is stimulated. In FIG. 327C, the first bipolenetwork (or a bipole pair) in the first region is energized 90532, andthe patient is monitored for a response 90534 to the stimulation. Thebipole pair in a second region is then energized 90536, and the patientis monitored for a response 90538. Additional energizing and monitoringsteps (not shown) may also be included for other regions of the device,if present. The responses to the different region can be compared 90542,and the device can be moved in response to the presence of a nerve inone or more of the regions 90546. Optionally, it may be determined whichregion of the device is closer to the nerve 90544. If the nerve isdetected, the tissue may be acted on (e.g., cut, ablated, removed, etc.,or the device may be further oriented by moving it, and these steps maybe repeated. If no nerve is detected, the steps may be repeated untilthe device is positioned as desired, and a procedure may then beperformed.

In some variations, the device may be used to position (or form apassage for) another device or a region of the device that acts on thetissue. For example, the device may be used to position a guide channelor guide wire. In some variations, the method may include repeatedlyenergizing only a subset of the bipole networks (or bipole pairs) untila nerve is detected, and then other bipole networks on the device may beenergized to determine with more accuracy the relationship (e.g.,orientation) of the nerve with respect to the device.

As mentioned, the step of monitoring or detecting a response may beperformed manually (e.g., visually), or using a sensor or sensor. Forexample, using an accelerometer may be coupled to muscle. Theaccelerometer may be a multiple axis accelerometer that detects themovement of the muscle in any direction, and movement coordinated withstimulation may be detected. In some variations, a strain gauge may beused on muscle innervated by a nerve passing through or originating inthe region of tissue being examined. The strain gauge may be a multipleaxis strain gauge that detects the movement of the muscle in anydirection. In some variations, an EMG probe may be used to measureevoked potentials of the muscle. The magnitude of any response may alsobe determined.

Systems

Any of the devices described herein may be used as part of a system,which may be referred to as a nerve localization system. Systems mayinclude components (e.g., hardware, software, or the like) to executethe methods described herein.

FIG. 328 is a block diagram of additional components of a system 90580for determining if a nerve is nearby a device. The components 90580shown in FIG. 328 may be used with any of the devices described herein,and may include any computing device, including a personal dataassistant, cellular telephone, laptop computer, or desktop computer. Thesystem may include a central processing unit (CPU) 90582, a randomaccess memory (RAM) 90584, a read only memory (ROM″) 90606, a display90588, a user input device 90612, a transceiver application specificintegrated circuit (ASIC) 90616, a digital to analog (D/A) and analog todigital (A/D) convertor 90615, a microphone 90608, a speaker 90602, andan antenna 90604. The CPU 90582 may include an OS module 90614 and anapplication module 90613. The RAM 90584 may include a queue 90598 wherethe queue 90598 may store signal levels to be applied to one or morebipolar modules 9046, 9048. The OS module 90614 and the applicationmodule 90613 may be separate elements. The OS module 90614 may execute acomputer system or controller OS. The application module 90612 mayexecute the applications related to the control of the system.

The ROM 90606 may be coupled to the CPU 90582 and may store programinstructions to be executed by the CPU 90582, OS module 90614, andapplication module 90613. The RAM 90584 is coupled to the CPU 90582 andmay store temporary program data, overhead information, and the queues90598. The user input device 90512 may comprise an input device such asa keypad, touch pad screen, track ball or other similar input devicethat allows the user to navigate through menus in order to operate thearticle 90580. The display 90588 may be an output device such as a CRT,LCD, LED or other lighting apparatus that enables the user to read,view, or hear user detectable signals.

The microphone 90608 and speaker 90602 may be incorporated into thedevice. The microphone 90608 and speaker 90602 may also be separatedfrom the device. Received data may be transmitted to the CPU 90582 via aserial bus 90596 where the data may include signals for a bipolenetwork. The transceiver ASIC 90616 may include an instruction setnecessary to communicate data, screens, or signals. The ASIC 90616 maybe coupled to the antenna 90604 to communicate wireless messages, pages,and signal information within the signal. When a message is received bythe transceiver ASIC 90616, its corresponding data may be transferred tothe CPU 90582 via the serial bus 90596. The data can include wirelessprotocol, overhead information, and data to be processed by the devicein accordance with the methods described herein.

The D/A and A/D convertor 90615 may be coupled to one or more bipolenetworks to generate a signal to be used to energize them. The D/A andA/D convertor 90615 may also be coupled to one or more sensors 90322,90324 to monitor the sensor 90322, 90324 state or condition.

Any of the components previously described can be implemented in anumber of ways, including embodiments in software. These may includehardware circuitry, single or multi-processor circuits, memory circuits,software program modules and objects, firmware, and combinationsthereof, as desired by the architect of the system 9010 and asappropriate for particular implementations of various embodiments.

EXAMPLE 1 Neural Localization when Treating Spinal Stenosis

One area of surgery which could benefit from the development of lessinvasive techniques including neural localization is the treatment ofspinal stenosis. Spinal stenosis often occurs when nerve tissue and/orblood vessels supplying nerve tissue in the lower (or “lumbar”) spinebecome impinged by one or more structures pressing against them, causingpain, numbness and/or loss of function in the lower back and/or lowerlimb(s). In many cases, tissues such as ligamentum flavum, hypertrophiedfacet joint and bulging intervertebral disc impinge a nerve root as itpasses from the cauda equine (the bundle of nerves that extends from thebase of the spinal cord) through an intervertebral foramen (one of theside-facing channels between adjacent vertebrae). Here we provide oneexample of a device for determining if a nerve is nearby that may beused as part of method for treating spinal stenosis.

FIG. 329 is a top view of a vertebra with the cauda equina shown incross section and two nerve roots branching from the cauda equina toexit the central spinal canal and extend through intervertebral foraminaon either side of the vertebra. FIG. 330 is a side view of the lumbarspine, showing multiple vertebrae, the intervertebral foramina betweenadjacent vertebrae, and the 1st-5th spinal nerves exiting the foramina.

Surgery may be required to remove impinging tissue and decompress theimpinged nerve tissue of a spinal stenosis. Lumbar spinal stenosissurgery typically involves first making an incision in the back andstripping muscles and supporting structures away from the spine toexpose the posterior aspect of the vertebral column. Thickenedligamentum flavum is then exposed by complete or partial removal of thebony arch (lamina) covering the back of the spinal canal (laminectomy orlaminotomy). In addition, the surgery often includes partial or completefacetectomy (removal of all or part of one or more facet joints), toremove impinging ligamentum flavum or bone tissue. Spinal stenosissurgery is performed under general anesthesia, and patients are usuallyadmitted to the hospital for five to seven days after surgery, with fullrecovery from surgery requiring between six weeks and three months. Manypatients need extended therapy at a rehabilitation facility to regainenough mobility to live independently.

Removal of vertebral bone, as in laminectomy and facetectomy, oftenleaves the affected area of the spine very unstable, requiring anadditional highly invasive fusion procedure that puts extra demands onthe patient's vertebrae and limits the patient's ability to move.Unfortunately, a surgical spine fusion results in a loss of ability tomove the fused section of the back, diminishing the patient's range ofmotion and causing stress on the discs and facet joints of adjacentvertebral segments. Such stress on adjacent vertebrae often leads tofurther dysfunction of the spine, back pain, lower leg weakness or pain,and/or other symptoms. Furthermore, using current surgical techniques,gaining sufficient access to the spine to perform a laminectomy,facetectomy and spinal fusion requires dissecting through a wideincision on the back and typically causes extensive muscle damage,leading to significant post-operative pain and lengthy rehabilitation.Thus, while laminectomy, facetectomy, and spinal fusion frequentlyimprove symptoms of neural and neurovascular impingement in the shortterm, these procedures are highly invasive, diminish spinal function,drastically disrupt normal anatomy, and increase long-term morbidityabove levels seen in untreated patients.

A number of devices, systems and methods for less invasive treatment ofspinal stenosis have been described, for example, in U.S. patentapplication Ser. Nos.: 11/250,332, entitled “Devices and Methods forSelective Surgical Removal of Tissue,” and filed Oct. 15, 2005, now U.S.Pat. No. 7,738,968; 11/375,265, entitled “Method and Apparatus forTissue Modification,” and filed Mar. 13, 2006, now U.S. Pat. No.7,887,538; and 11/535,000, entitled Tissue Cutting Devices and Methods,”and filed Sep. 25, 2006, now Publication No. US-2008-0033465-A1, all ofwhich applications are hereby incorporated fully be reference herein.

Challenges in developing and using less invasive or minimally invasivedevices and techniques for treating neural and neurovascular impingementinclude accessing hard-to-reach target tissue and locating nerve tissueadjacent the target tissue, so that target tissue can be treated anddamage to nerve tissue can be prevented. These challenges may provedaunting, because the tissue impinging on neural or neurovascular tissuein the spine is typically located in small, confined areas, such asintervertebral foramina, the central spinal canal and the lateralrecesses of the central spinal canal, which typically have very littleopen space and are difficult to see without removing significant amountsof spinal bone. The assignee of the present invention has described anumber of devices, systems and methods for accessing target tissue andidentifying neural tissue. Exemplary embodiments are described, forexample, in U.S. patent application Ser. Nos.: 11/251,205, entitled“Devices and Methods for Tissue Access,” and filed Oct. 15, 2005, nowU.S. Pat. No. 7,918,849; 11/457,416, entitled “Spinal Access and NeuralLocalization,” and filed Jul. 13, 2006, now U.S. Pat. No. 7,578,819; and11/468,247, entitled “Tissue Access Guidewire System and Method,” andfiled Aug. 29, 2006, now U.S. Pat. No. 7,857,813, all of whichapplications are hereby incorporated fully be reference herein.

The methods and devices for neural localization described herein may beused in less invasive spine surgery procedures, including the treatmentof spinal stenosis. For example, the methods and devices describedherein can be used with minimal or no direct visualization of the targetor nerve tissue, such as in a percutaneous or minimally invasivesmall-incision procedure.

FIG. 331 illustrates one device for treatment of spinal stenosisincluding a tissue cutting device 901000 including a guidewire. Forfurther explanation of guidewire systems and methods for insertingdevice 901000 and other tissue removal or modification devices,reference may also be made to U.S. U.S. Pat. No. 7,857,813 and U.S.patent application Ser. No. 11/468,252, now Publication No.US-2008-0086034-A1, both titled “Tissue Access Guidewire System andMethod,” and both filed Aug. 29, 2006, the full disclosures of which arehereby incorporated by reference.

Cutting device 901000 may be at least partially flexible, and in someembodiments may be advanced through an intervertebral foramen IF of apatient's spine to remove ligamentum flavum LF and/or bone of a vertebraV, such as hypertrophied facet (superior articular process SAP in FIG.331), to reduce impingement of such tissues on a spinal nerve SN and/ornerve root. In one embodiment, device 901000 cuts tissue by advancing aproximal blade 901012 on an upper side of device 901000 toward a distalblade 901014. This cutting device may be used with (or as part of) asystem for determining if a nerve is nearby, and may prevent damage tonerves in the region which the device operates.

In various embodiments, device 901000 may be used in an open surgicalprocedure, a minimally invasive surgical procedure or a percutaneousprocedure. In any procedure, it is essential for a surgeon to know thatdevice 901000 is placed in a position to cut target tissue, such asligament and bone, and to avoid cutting nerve tissue. In minimallyinvasive and percutaneous procedures, it may be difficult or impossibleto directly visualize the treatment area, thus necessitating some othermeans for determining where target tissue and neural tissue are locatedrelative to the tissue removal device. At least, a surgeon performing aminimally invasive or percutaneous procedure will want to confirm thatthe tissue cutting portion of device 901000 is not directly facing andcontacting nerve tissue. The various nerve localization devices andsystems described herein may help the surgeon verify such nerve/devicelocation. A neural localization system and method may be used inconjunction with device 901000 or with any other tissue removal, tissuemodification or other surgical devices. Furthermore, various embodimentsmay have applicability outside the spine, such as for locating nervetissue in or near other structures, such as the prostate gland, thegenitounrinary tract, the gastrointestinal tract, the heart, and variousjoint spaces in the body such as the knee or shoulder, or the like.Therefore, although the following description focuses on the use ofembodiments of the invention in the spine, all other suitable uses forthe various embodiments described herein are also contemplated.

Referring now to FIG. 332, a diagrammatic representation of oneembodiment of a nerve tissue localization system 901020 is shown. Neurallocalization system 901000 may include an electronic control unit 901024and a neural stimulation probe 901024, a patient feedback device 901026,a user input device 901028 and a display 901030, all coupled withcontrol unit 901022.

In one embodiment, electronic control unit (ECU) 901020 may include acomputer, microprocessor or any other processor for controlling inputsand outputs to and from the other components of system 901020. In oneembodiment, for example, ECU 901020 may include a central processingunit (CPU) and a Digital to Analog (D/A) and Analog to Digital Converter(A/D). ECU 901022 may include any microprocessor having sufficientprocessing power to control the operation of the D/A A/D converter andthe other components of system 901020. Generally, ECU 901022 may controlthe operation of the D/A A/D converter and display device 901030, insome embodiments based on data received from a user via user inputdevice 901028, and in other embodiments without input from the user.User input device 901028 may include any input device or combination ofdevices, such as but not limited to a keyboard, mouse and/or touchsensitive screen. Display device 901030 may include any output device orcombination of devices controllable by ECU 901022, such as but notlimited to a computer monitor, printer and/or other computer controlleddisplay device. In one embodiment, system 901020 generates electricalsignals (or other nerve stimulating energy signals in alternativeembodiments), which are transmitted to electrodes on probe 901024, andreceives signals from patient feedback device 901026 (or multiplefeedback devices 901026 in some embodiments). Generally, ECU 901022 maygenerate a digital representation of signals to be transmitted byelectrodes, and the D/A A/D converter may convert the digital signals toanalog signals before they are transmitted to probe 901024. ECU 901022also receive a return current from probe 901024, convert the current toa digital signal using the D/A A/D converter, and process the convertedcurrent to determine whether current was successfully delivered to thestimulating portion of probe 901024. The D/A A/D converter may convertan analog signal received by patient feedback device(s) 901026 into adigital signal that may be processed by ECU 901022. ECU 901022 may holdany suitable software for processing signals from patient feedbackdevices 901026, to and from probe 901024 and the like. According tovarious embodiments, display device 901030 may display any of a numberof different outputs to a user, such as but not limited to informationdescribing the signals transmitted to probe 901024, verification thatstimulating energy was successfully delivered to a stimulating portionof probe 901024, information describing signals sensed by patientfeedback devices 901026, a visual and/or auditory warning when a nervehas been stimulated, and/or the like. In various alternativeembodiments, system 901020 may include additional components or adifferent combination or configuration of components, without departingfrom the scope of the present invention.

The neural stimulation probe 901024 is an elongate body having an outersurface including one or more regions with a bipole pair or bipolenetwork. Furthermore, any suitable number of regions may be included ona given probe 901024. In various embodiments, for example, probe 901024may includes two or more regions, each having a bipole pair or bipolenetwork (comprising a plurality of bipole pairs) disposed along theprobe in any desired configuration. In one embodiment, probe 901024 mayinclude four regions, each having at least one bipole pairs, one pair oneach of top, bottom, left and right sides of a distal portion of theprobe that is configured to address neural tissue.

In some embodiments, ECU 901022 may measure current returned throughprobe 901024 and may process such returned current to verify thatcurrent was, in fact, successfully transmitted to a nerve stimulationportion of probe 901024. In one embodiment, if ECU 901022 cannot verifythat current is being transmitted to the nerve stimulation portion ofprobe 901024, ECU 901022 may automatically shut off system 901020. In analternative embodiment, if ECU 901022 cannot verify that current isbeing transmitted to the nerve stimulation portion of probe 901024, ECU901022 may signal the user, via display device 901030, that probe 901024is not functioning properly. Optionally, in some embodiments, system901020 may include both a user signal and automatic shut-down.

Patient feedback device 901026 may include any suitable sensing deviceand typically includes multiple devices for positioning at multipledifferent locations on a patient's body. In some embodiments, forexample, multiple motion sensors may be included in system 901020. Suchmotion sensors may include, but are not limited to, accelerometers,emitter/detector pairs, lasers, strain gauges, ultrasound transducers,capacitors, inductors, resistors, gyroscopes, and/or piezoelectriccrystals. In one embodiment, where nerve tissue stimulation system901020 is used for nerve tissue detection in the lumbar spine, feedbackdevice 901026 may include multiple accelerometers each accelerometerattached to a separate patient coupling member, such as an adhesive pad,for coupling the accelerometers to a patient. In one such embodiment,for example, each accelerometer may be placed over a separate musclemyotome on the patients lower limbs.

When nerve tissue is stimulated by probe 901024, one or more patientfeedback devices 901026 may sense a response to the stimulation anddeliver a corresponding signal to ECU 901022. ECU 901022 may processsuch incoming signals and provide information to a user via displaydevice 901030. For example, in one embodiment, information may bedisplayed to a user indicating that one sensor has sensed motion in aparticular myotome. As part of the processing of signals, ECU 901022 mayfilter out “noise” or sensed motion that is not related to stimulationby probe 901024. In some embodiments, an algorithm may be applied by ECU901022 to determine which of multiple sensors are sensing the largestsignals, and thus to pinpoint the nerve (or nerves) stimulated by probe901024.

In an alternative embodiment, patient feedback device 901026 may includemultiple electromyography (EMG) electrodes. EMG electrodes receive EMGor evoked muscle action potential (EMAP) signals generated by muscleelectrically coupled to EMG electrodes and to a depolarized nerve (motorunit). One or more nerves may be depolarized by one or more electricalsignals transmitted by probe. As with the motion sensor embodiment, ECU901022 may be programmed to process incoming information from multipleEMG electrodes and provide this processed information to a user in auseful format via display device 901030.

User input device 901028, in various embodiments, may include anysuitable knob, switch, foot pedal, toggle or the like and may bedirectly attached to or separate and coupleable with ECU 901022. In oneembodiment, for example, input device 901028 may include an on/offswitch, a dial for selecting various bipolar electrode pairs on probe901024 to stimulate, a knob for selecting an amount of energy totransmit to probe 901024 and/or the like.

Referring now to FIG. 333, in one embodiment, a nerve tissuelocalization system 901040 may include an ECU 901042, a neuralstimulation probe 901044, multiple patient feedback devices 901026, anda user input device 9048. Probe 901044 may include, in one embodiment, acurved, flexible nerve stimulating elongate member 901058, which mayslide through a rigid cannula 901056 having a handle 901054.

The probe 901044 is a device for determining if a nerve is nearby aregion of the device, and includes a plurality of regions which eachinclude one or more bipole pairs. In some variations the probe 901044includes two regions (an upper region and a lower region), and eachregion includes a bipole network configured to form a continuous bipolefield along the length of the probe in either the upper or lowerregions. A nerve stimulating member 901058 may include a guidewire lumenfor allowing passage of a guidewire 901059, for example after nervetissue has been detected to verify that the curved portion of nervestimulating member 901058 is in a desired location relative to targettissue TT and nerve tissue NT. Patient feedback devices 901046 and probe901044 may be coupled with ECU 901042 via wires 901050 and 901052 or anyother suitable connectors. ECU 901042 may include user input device901048, such as a knob with four settings corresponding to top, bottom,left and right sides of a nerve tissue stimulation portion of nervestimulating member 901058. ECU 901042 may also optionally include adisplay 901047, which may indicate an amount of muscle movement sensedby an accelerometer feedback device 901046. In one embodiment, ECU901042 may include one or more additional displays, such as red andgreen lights 901049 indicating when it is safe or unsafe to perform aprocedure or whether or not probe 901044 is functioning properly. Anyother suitable displays may additionally or alternatively be provided,such as lamps, graphs, digits and/or audible signals such as buzzers oralarms.

In one embodiment, each of patient feedback devices 901046 may includean accelerometer coupled with an adhesive pad or other patient couplingdevice. In one embodiment, a curved portion of nerve stimulating member901058 may be configured to pass from an epidural space of the spine atleast partway through an intervertebral foramen of the spine. In otherembodiments, nerve stimulating member 901058 may be straight, steerableand/or preformed to a shape other than curved.

FIGS. 334A-334B and 334B describe a method for localizing nerve tissueand placing a guidewire in a desired location in a spine using thedevice configured to determine if a nerve is nearby. Before advancing anerve tissue localization probe into the patient, and referring again toFIG. 333, multiple patient feedback devices 901046, such asaccelerometers or EMG electrodes, may be placed on the patient, and ECU901042 may be turned on. In one embodiment, a test current may betransmitted to probe 901044, and a return current from probe 901044 maybe received and processed by ECU 901042 to verify that probe 901044 isworking properly.

As shown in FIG. 334A, an epidural needle 901060 (or cannula) may bepassed through the patient's skin, and a distal tip of needle 901060 maybe advanced through the ligamentum flavum LF of the spine into theepidural space ES. Next, as shown in FIG. 334B, a probe that isconfigured to determine if a nerve is nearby the probe 901062 may bepassed through epidural needle 901060, such that a curved, flexible,distal portion passes into the epidural space ES and through anintervertebral foramen IF of the spine, between target tissue(ligamentum flavum LF and/or facet bone) and non-target neural tissue(cauda equina CE and nerve root NR). As shown in FIG. 334C, the upperregion of the probe having a first bipole network may be energized togenerate a bipole field as current passes between the anodes andcathodes of the bipole network in the upper region 901062. In somevariations, the bipole pairs may be monitored to confirm thattransmitted energy returned proximally along the probe, as describedpreviously. As shown in FIG. 334D, the lower bipole network may then beenergized to generate a bipole field from the curved portion of probe901062. In an alternative embodiment, energy may be transmitted only tothe top, only to the bottom, or to the bottom first and then the topregions. In some embodiments, energy may be further transmitted toelectrodes on left and right regions of probe 901062. Depending on theuse of a given probe 901062 and thus its size constraints and themedical or surgical application for which it is being used, any suitablenumber of electrodes may form the bipole network of a particular region.

As energy is transmitted to the bipole network in any region of theprobe 901062, patient response may be monitored manually or via multiplepatient feedback devices (not shown in FIG. 334), such as, but notlimited to, accelerometers or EMG electrodes. In one method, the sameamount of energy may be transmitted to the bipole network in thedifferent regions of the probe in series, and amounts of feedback sensedto each transmission may be measured and compared to help localize anerve relative to probe 901062. If a first application of energy doesnot generate any response in the patient, a second application of energyat higher level(s) may be tried and so forth, until a general locationof nerve tissue can be determined. In an alternative embodiment, themethod may involve determining a threshold amount of energy required bybipole network to stimulate a response in the patient. These thresholdamounts of energy may then be compared to determine a general locationof the nerve relative to the probe. In another alternative embodiment,some combination of threshold and set-level testing may be used.

In one embodiment, as shown in FIG. 334E, nerve probe 901062 may includea guidewire lumen through which a guidewire may be passed, once it isdetermined that device 901062 is placed in a desired position betweentarget and non-target tissue (e.g., avoiding a nerve adjacent to theupper region). As shown in FIG. 334F, when epidural needle 901060 andprobe 901062 are removed, guidewire 901064 may be left in place betweentarget tissue (such as ligamentum flavum LF and/or facet bone) andnon-target tissue (such as cauda equina CE and nerve root NR). Any of anumber of different minimally invasive or percutaneous surgical devicesmay then be pulled into the spine behind guidewire 901064 or advancedover guidewire 901064, such as the embodiment shown in FIG. 331 andothers described by the assignee of the present application in otherapplications incorporated by reference herein.

Referring now to FIGS. 335A-335H, another embodiment of a method foraccessing an intervertebral foramen IF and verifying a location of aprobe relative to tissue (such as ligamentum flavum LF and nerve/nerveroot NR tissue) is demonstrated. In this embodiment, as shown in FIG.335A, an access cannula 901070 may be advanced into the patient over anepidural needle 901072 with attached syringe. As shown in FIG. 335B,cannula 901070 and needle 901072 may be advanced using a loss ofresistance technique, as is commonly performed to achieve access to theepidural space via an epidural needle. Using this technique, when thetip of needle 901072 enters the epidural space, the plunger on thesyringe depresses easily, thus passing saline solution through thedistal end of needle 901072 (see solid-tipped arrows). As shown in FIG.335C, once epidural access is achieved, needle can be withdrawn from thepatient, leaving cannula in place with its distal end contacting or nearligamentum flavum LF. Although needle 901072 may be removed, its passagethrough ligamentum flavum LF may leave an opening 901073 (or path, trackor the like) through the ligamentum flavum LF.

As shown in FIG. 335D, a curved, flexible guide 901074 having anatraumatic distal tip 901075 may be passed through cannula 901070 andthrough opening 901073 in the ligamentum flavum LF, to extend at leastpartway through an intervertebral foramen IF. In this variation, theguide 901074 is configured as a device for determining if a nerve isnearby a region of the device. The guide 901074 is an elongate memberthat includes at least a first region having a bipole pair, or morepreferably a bipole network thereon.

In FIG. 335E, a first bipole network on or near an external surface ofguide 901074 may then be energized, and the patient may be monitored forresponse. As in FIG. A7F, a second bipole network disposed along guide901074 in a different circumferential region than the region may beenergized, and the patient may again be monitored for response. Thisprocess of activation and monitoring may be repeated for any number ofbipole networks or as the device is manipulated in the tissue, accordingto various embodiments. For example, in one embodiment, guide 901074 mayinclude a first region having a bipole network on its top side (innercurvature), a second region having a bipole network on the bottom side(outer curvature), and a third and fourth region each having a bipolenetwork on the left side and right side, respectively. A preselectedamount of electrical energy (current, voltage, and/or the like) may betransmitted to a bipole network, and the patient may be monitored for anamount of response (EMG, muscle twitch, or the like). The same (or adifferent) preselected amount of energy may be transmitted to a secondbipole network, the patient may be monitored for an amount of response,and then optionally the same amount of energy may be transmittedsequentially to third, fourth or more bipole networks, while monitoringfor amounts of response to each stimulation. The amounts of response maythen be compared, and from that comparison a determination may be madeas to which region is closest to nerve tissue and/or which region isfarthest from nerve tissue.

In an alternative method, energy may be transmitted to a first bipoleelectrode and the amount may be adjusted to determine a threshold amountof energy required to elicit a patient response (EMG, muscle twitch, orthe like). Energy may then be transmitted to a second bipole network,adjusted, and a threshold amount of energy determined. Again, this maybe repeated for any number of bipole networks (e.g., regions). Thethreshold amounts of required energy may then be compared to determinethe location of the regions relative to nerve tissue.

Referring now to FIG. 335G, once it is verified that guide 901074 is ina desired position relative to nerve tissue and/or target tissue, aguidewire 901076 may be passed through guide and thus through theintervertebral foramen IF and out the patient's skin. Cannula 901070 andguide 901074 may then be withdrawn, leaving guidewire 901076 in place,passing into the patient, through the intervertebral foramen, and backout of the patient. Any of a number of devices may then be pulled behindor passed over guidewire 901076 to perform a procedure in the spine.

Rotating a Tight Bipole Pair

Another variation of nerve localizing device including one or more tightbipole pairs is a device having at least one tight bipole pair that canbe scanned (e.g., rotated) over at least a portion of the circumferenceof the device to detect a nearby nerve.

In general, a device having a movable tight bipole pair may include anelongate body that has an outer surface and at least one bipole pairthat can be scanned (moved) with respect to the outer surface of thedevice so as to be energized in different regions of the outer surfaceof the device to determine if a nerve is nearby. For example, a devicemay include an elongate body having an outer surface that can be dividedup into a plurality of circumferential regions and a scanning that ismovable with respect to the outer surface. At least one tight bipolepair (or a bipole network) is attached to the scanning surface, allowingthe bipole pair or network to be scanned to different circumferentialregions.

FIGS. 336A and 336B illustrate variations of a device having a scanningor movable bipole pair (or bipole network). For example, FIG. 336Aincludes an elongate body 902801 having an outer surface. In thisvariation the elongate body has a circular or oval cross-section,although other cross-sectional shapes may be used, includingsubstantially flat. The surface of the outer body includes a window902803 region exposing a scanning surface 902807 to which at least onebipole pair is connected. The scanning surface may be moved relative tothe outer surface (as indicated by the arrow). In this example, thewindow extends circumferentially, and the scanning surface may bescanned radially (e.g., up and down with respect to the window).

FIG. 336B illustrates another variation, in which the distal end of theelongate body 902801′ is rotatable with respect to the more proximalregion of the device. The distal end includes one or more bipole pairs.In FIG. 336 the rotatable distal end includes a bipole network 902819.The bipole network may be energized as it is rotated, or it may berotated into different positions around the circumference of the deviceand energized after it has reached each position.

The devices illustrated in FIGS. 336A and 336B may include a controllerconfigured to control the scanning (i.e., rotation) of the bipole pair.The device may also include a driver for driving the motion of thebipole pair. For example, the drive may be a motor, magnet, axel, shaft,cam, gear, etc. The controller may control the driver, and may controlthe circumferential position of the bipole pair (or bipole network). Thedevice may also include an output for indicting the circumferentialregion of the bipole network or pair.

In operation, the scanning bipole pair can be used to determine if anerve is near the device by moving the bipole pair or network withrespect to the rest of the device (e.g., the outer surfaced of theelongate body). For example, the device may be used to determine if anerve is nearby the device by scanning the bipole pair (or a bipolarnetwork comprising a plurality of bipole pairs) across a plurality ofcircumferential regions of the outer surface of the elongate body, andby energizing the bipole pair(s) when it is in one of thecircumferential regions. As mentioned, the bipole pair(s) may beenergized as they are moved, or they may be energized once they are inposition. The movement may be reciprocal (e.g., back and forth) orrotation, or the like.

Tissue Manipulation Tools

Any appropriate tissue manipulation device or tool may be used with thetight bipole networks described herein, allowing the tissue manipulationdevices to detect the presence of a nerve in a tissue that is to bemanipulated by the device. Confirmation that a nerve either is, or isnot, in a tissue that is targeted by a tissue manipulation device may beinvaluable in preventing or reducing the likelihood of injury whenperforming procedures using the tools.

Tools that include a cavity or other tissue receiving portion are ofparticular interest. Such tools typically include a tissue receivingportion including at least one tissue receiving surface into which thepatient's tissue will be received for manipulation. The tissue receivingsurface(s) of the tool may include a tight bipole network that isconfigured to emit a broadcast field that is limited to the tissuereceiving portion but sufficient to stimulate a nerve within the tissuereceiving portion.

In practice, the tissue manipulation device may be any device thatincludes a tissue receiving portion which can include a tight bipolenetwork. For example, a tissue manipulation device may include arongeur, a scissor, a clam, a tweezers, or the like.

FIGS. 337A-337E (and 319D) illustrate rongeurs, one type of a tissuemanipulation tool that may include a tight bipole network. In therongeur example shown in FIGS. 337A through 337C, the device includes atissue receiving portion 902903 configured as a mouth or cavity. Thetight bipole network is arranged in the tissue receiving portion toprovide feedback to a surgeon or other user that the tissue to be cut bythe rongeur (in the cavity) does or does not include a nerve. In manyapplications the rongeur can be used for cutting through bone, ligament,and the like, as part of a procedure during which it may be undesirableto cut or damage nearby nerves.

The distal end region of the rongeur illustrated in FIGS. 337A-337Eincludes a blunted distal end region, and a cavity along the lateralside region of the device (oriented up in these figures), formed by aslideable biting surface 902901 that can move back and forth to bitedown on tissue within the tissue receiving portion 902903. In FIG. 337Athe ‘bottom’ of the tissue receiving region includes a tight bipolenetwork arranged along the length of the bottom (e.g., in thelongitudinal direction down the long axis of the device). In thisexample, a plurality of anodes is formed by openings to a single annodalconductor, and a plurality of cathodes is formed by opening to a singlecathodal conductor. The anodes and cathodes 902911 are arranged instaggered fashion across the surface, as shown in the partial view ofFIG. 337A1. In some variations the other walls forming the tissuereceiving portion may also include anodes and/or cathodes forming a partof (or a complete) tight bipole network. In the example shown in FIG.337A1, the tight bipole pairs can be formed from an insulated flexcircuit.

FIGS. 337B and 337C illustrate the operation of the rongeur of FIG. 337Ain use, when a nerve 902909 is present in the mouth of the device. FIG.337C is a partial cross-section of the nerve and the tight bipolenetwork region of the device, showing schematically a portion of thetight bipole emitted field between one of the anodes and cathodes,intersecting the nerve. Stimulation of the never by the emitted fieldwithin the tissue receiving portion of the rongeur will activate thenerve, and can be detected using one of the means described herein,including EMG, muscle twitch, or direct detection of nerve activation.

In operation, this sort of ‘smart tool’ (e.g., rongeur) can be used byfirst inserting it into a tissue region to be modified. For example, arongeur that can detect the presence of a nerve in the cutting mouth canbe used to cut bone or ligament within the spine as part of a spinaldecompression. The tool may be inserted during an open procedure orduring a minimally invasive procedure (particularly for flexible toolsthat may include visualization). The mouth or jaw region of the device(the tissue receiving portion) may be positioned against tissue so thatthe tissue is within the tissue receiving portion, and the tight bipolenetwork may be stimulated. The patient can be simultaneously monitoredfor activation of a nerve from the region of the tissue in the mouth orjaw of the device. For example, if the device is used as part of aspinal decompression, an EMG or accelerometer-based system may be usedto monitor for muscle twitch upon activation of the tight bipolenetwork.

Because the tight bipole network is configured to have a controlledbroadcast field that does not substantially extend beyond the mouth ofthe tool, activation of a nerve will only occur if the nerve is withinthe mouth or jaw of the device. This information may be displayed, ormay be feed back to the tool to prevent it from compressing or cuttingthe tissue in the tissue receiving portion of the device, therebyavoiding damage to the nerve. The tight bipole network is configured tolimit the emitted field, as described above. The field emitted by atight bipole network is limited by the position and configuration of(e.g., sizes and separation between) the anode and cathode. As indicatedabove, the emitted field in these devices is substantially limited tothe tissue receiving portion, so that only a nerve within the tissuereceiving portion would be stimulated. Although some of the emittedfield may escape the boundaries of the tissue receiving portion, themajority of the field is concentrated in the tissue receiving portion.

FIG. 337D shows another variation of a rongeur having a tight bipolenetwork. The distal end region of the rongeur in FIG. 337D isstructurally similar to the rongeur shown in FIG. 337A-337C, however thetight bipole network is arranged differently. In this example, the twoside surfaces of the tissue receiving portion each include a tightbipole pair 902905, 902906. One of the side surfaces 902923 is thesurface of the movable biting member 902905 that faces into the tissuereceiving portion. The opposite wall 902921 is stationary relative tothe biting surface 902901. Thus, the opposite walls 902921, 902923 ofthe tissue receiving portion each have at least one bipole pair formingthe bipole network.

FIG. 337E shows a similar variation, in which the anodes and cathodes ofthe tight bipole network are on opposite walls 902921, 902923 of thetissue receiving portion. In this example, the anodes 902915, 902916 areon the movable biting member 902905, and the cathodes 902917, 902918 areon the opposite wall 902921. In some variations both the opposite wallsand the bottom of the tissue receiving portion (e.g., all of thesurfaces of the tissue receiving portion) may have anodes and/orcathodes of the tight bipole network.

Systems for Controlling Tools

As described above, and illustrated in FIGS. 325A and 325B, anaccelerometer-based detection system may be used to determine when anerve has been stimulated. An accelerometer-based system for determiningif a nerve is nearby a tool having a neurostimulation electrode may beused with any appropriate neurostimulation electrode, and is not limitedto the tight bipole pair devices and systems that are described herein.Thus, an accelerometer-based system may be used with a monopolarneurostimulation electrode, a bipolar neurostimulation electrode, or amultipolar neurostimulation electrode, as well as the tight bipolenetworks described above.

In general, an accelerometer-based detection system for determining if anerve is nearby an insertable tool having a neurostimulation electrodeincludes an accelerometer that is configured to detect muscle twitch, afeedback controller, and a tool having at least one neurostimulationelectrode. FIG. 338 schematically illustrates these elements, as well asother optional features.

In FIG. 338, the accelerometer configured to detect muscle twitch 903001is shown connected to a feedback controller 903003. Any appropriateaccelerometer may be used, including low-g triaxial accelerometers, asmentioned above. More than one accelerometer may be used. Theseaccelerometers may be adapted or configured specifically for detectionof muscle twitch by including filtering or sensitivity adjustment. Forexample, the accelerometers may be filtered to prevent low-frequencystimulation that may result from movement artifact not linked tostimulation by the neurostimulation electrode. The signal output fromthe accelerometer(s) may be processed on-board the accelerometer 903001,or may be processed within the feedback controller 903003. In somevariations, the feedback controller is integrated with theaccelerometer(s).

The accelerometers are typically secured to the patient, and may besecured to the outside of the patient (e.g., the skin of the patient, ora garment worn by the patient, etc.). In some variations, theaccelerometer is implanted within the patient.

The feedback controller 903003 receives output from the accelerometer,and may also receive output from the controller/power source 903007 forthe neurostimulation electrode on the insertable tool. The controller903003 may coordinate this input to determine if stimulation by theneurostimulation electrode has resulted in muscle twitch. For example,the controller may compare the timing of the applied neurostimulationand any detected muscle twitch. In some variations the neurostimulationmay be applied in a pattern (e.g., duration on/duration off) that may becompared to the pattern of detected muscle twitch by the controller903003. This comparison may confirm the activation of a nerve, andtherefore confirm that a nerve is being activated by theneurostimulation electrode. The result of any processing by the feedbackcontroller may be output. For example, signals from the feedbackcontroller may be visually output. A display or monitor may indicateactivation of a nerve by the neurostimulation electrode. In somevariations, the output is a light (e.g., an LED or other color-codedsignal) indicating stimulation of the nerve. Multiple neurostimulationelectrodes may be used, and the feedback controller may indicate (viaoutput) nerve activation relative to each neurostimulation electrode. Insome variations, the output from the controller 903003 may be audible,from a speaker or speakers. For example, the output may buzz orotherwise indicate proximity to a nerve. More than one output modalitymay be used. In some variations the signal of the accelerometer(s) maybe directly output.

Accelerometer-based systems for detecting neurostimulation describedherein may be advantageous over comparable EMG systems, since they donot require the electronic amplification systems and technical expertiseneeded for use with comparable EMG systems. EMG systems typicallyrequire recording and analysis of EMG signals during or followingneurostimulation. This analysis is typically done by a person trained tointerpret the often complex EMG signals. In contrast the output of theaccelerometer (sensing muscle twitch) may be readily output andunderstood without requiring a technician to interpret the output.

The system may also include feedback that helps control the insertabletool. In addition to the output seen, heard, or otherwise sensed by auser manipulating a tool having a neurostimulation electrode, thefeedback controller may send data or control signals back to the tool toregulate its activity. For example, if the tool is a cutting or bitingtool such as the rongeurs described above, a signal from the feedbackcontroller indicating that a nerve has been detected may be sent to thetool (or a controller for the tool) to prevent it from cutting orcompressing the tissue, thereby protecting the sensed nerve from damage.As another example, the tool may be a probe or hook (e.g., a love hook)to be used to manipulate the nerve (e.g., by pushing or protecting it.Feedback from the feedback controller 903003 may be used to activate theprobe or hook, allowing it to move and thereby manipulate the nerve. Thetool may also be a therapy-delivery device that is activated when inproximity to a target nerve. Feedback from the accelerometer-basedsystem may trigger the release of the therapy. In one example, thetherapy is a drug to be delivered.

The examples and illustrations included herein show, by way ofillustration and not of limitation, specific embodiments in which thesubject matter may be practiced. Other embodiments may be utilized andderived therefrom, such that structural and logical substitutions andchanges may be made without departing from the scope of this disclosure.Such embodiments of the inventive subject matter may be referred toherein individually or collectively by the term “invention” merely forconvenience and without intending to voluntarily limit the scope of thisapplication to any single invention or inventive concept, if more thanone is in fact disclosed. Thus, although specific embodiments have beenillustrated and described herein, any arrangement calculated to achievethe same purpose may be substituted for the specific embodiments shown.This disclosure is intended to cover any and all adaptations orvariations of various embodiments. Combinations of the aboveembodiments, and other embodiments not specifically described herein,will be apparent to those of skill in the art upon reviewing the abovedescription.

Access and Tissue Modification Systems and Methods

As mentioned, described herein are devices, systems and method fortreating tissue by first placing a guidewire (or “pullwire”) in positionwithin the body, and then using the guidewire to position, anchor and/ortreat the tissue. In general, these methods and systems are “bimanual”procedures, in which the implant or tissue modification device iscontrolled within the body from two separate locations outside of thebody, and by manipulating the implant/device from both the distal andproximal ends.

These systems and methods may be particularly useful for percutaneoustreatments of one or more body region. However, it should be understoodthan any of the devices, methods and systems described herein may beused as part of an “open” surgical procedure in which access to a bodyregion is created through an opening in the tissue (e.g., by removal oftissue). Any of the systems and devices described may be performed aspart of a procedure that is at least partially open. Partiallypercutaneous procedures may also be performed using these devices,systems and methods.

FIGS. 340A-340F illustrate components a system that may be used to treattissue as described herein. The components illustrated in FIGS.340A-340F include: two variations of probes (340A and 340B) that may beused to position a guidewire (or pullwire) in the tissue, a neurallocalization device (FIG. 340C) that is configured to be coupled to theproximal end of a guidewire, a tissue modification device (FIG. 340D)that is configured to scrape or cut tissue and be coupled distally tothe proximal end of a guidewire, as well as a guidewire (FIG. 340F) anda handle that may be secured to the distal end of the guidewire (FIG.340E) allowing manipulation of the distal end of the guidewire/pullwire.

In particular, the guidewire, guidewire handle and placement probes(FIGS. 340A, 340B, 340E and 340F) may be used with one or moreadditional components to treat a patient, as illustrated in the examplesbelow. In general, these devices may be used to place the guidewire inposition within the body so that the (often sharp) distal end of theguidewire extends from the body, and the distal end of the guidewire(which may be adapted to couple to another device so that force can beapplied by pulling on the guidewire) extends from a second location inthe body.

As mentioned, the proximal end of the guidewire may be adapted to coupleto another device or devices. Examples of guidewires that may be usedare described, for example, in co-pending application Ser. No.11/468,247, titled “TISSUE ACCESS GUIDEWIRE SYSTEM AND METHOD” (filedAug. 29, 2006), now U.S. Pat. No. 7,857,813, and Ser. No. 12/127,535,titled “GUIDEWIRE EXCHANGE SYSTEMS TO TREAT SPINAL STENOSIS” (filed May27, 2008), now Publication No. US-2008-0275458-A1. The distal end of theimplant or device to be positioned and/or manipulated may also beadapted to couple to the guidewire as described.

Described herein is a guidewire- or pullwire-based system fordistracting a bone or region including bone. These methods may be usedto distract bone to treat a compression fracture (e.g., a spinalcompression fracture) or to separate bones or bony regions to allowaccess for further treatment. For example, an access system such as apullwire-based system can be used to deliver a percutaneous distractionsystem for distracting the inner spinous process and delivering an innerspinous process distraction device (IPD). Thus, in some variations,described herein are percutaneous inner spinous distraction access anddecompression systems, devices and methods of using them.

FIGS. 339 and 1 illustrate sections through a normal spine region,including the inter spinous process region. FIG. 339 shows a mediansagital section of two lumbar vertebra and their ligaments. In FIG. 339,the section through a region of spine illustrates the inter-spinalligament 95101 connected between two spinous processes 95103, 95103′.FIG. 1 illustrates a transverse section through the spine, showing thelamina and the superior and transverse processes.

As described in greater detail below, an inner spinous processdistraction device (IPD) may be inserted using the pullwire system. Thismethod of distracting the spinous processes may be used in conjunctionwith (or as part of) a procedure for decompressing the spine includingdelivering a transforaminal guide through the foramen. With the IPDholding a foramina open, a decompression procedure can be performed.

One variation of an inner spinous distraction access and decompressionkit is shown in FIG. 341A-341J. Some of the components illustrated inFIGS. 341A-341J are redundant, and may be omitted. Many of theseelements are also similar or identical to the elements shown in FIGS.340A-340F, and may be used with these elements. For example, a systemfor inserting a IPD may include a probe for inserting and positioning aguidewire/pullwire, a pullwire that is adapted to couple to the distalend of a IPD (or a carrier for the IPD), an IPD, and an IPD deliverytool that holds the IPD and may include a proximal handle ormanipulator. Examples of these elements are shown in FIGS. 341A and 341B(probes for positioning the guidewire, including an epidural needle anda curved IPD guide), FIG. 341C (pullwire/guidewire), and FIG. 341E (IPDdelivery tool or carrier with attached IPD). Additional components ofthis system may also include a sizer (FIG. 341D), a lock or locker forsecuring the IPD in position (FIG. 341F), and a handle for the distalend of the pullwire/guidewire (FIG. 341J). In addition, the system shownin FIGS. 341A-341J may also include elements that may be used for thedecompression of other spinal regions, including the foramen of thespine. For example, the system may include an additional probe (FIG.341G) that is shaped and sized for transforamenal access, as well as atissue modification member (FIG. 341I), and an additionalguidewire/pullwire (FIG. 341H).

In general, the probe element is an elongate, somewhat rigid andcannulated structure. In some variations the guide includes a curved orcurvable distal end region. For example, the probe may include an innercannula that can be extend distally from the outer cannula; the innercannula may curve as it is extend, allowing steering of the devicearound a body region. In general, the pullwire/guidewire may be extendedthrough the probe, into the body, around a target tissue region, andthen allowed to pass back through and out of the body from a secondregion. More than one probe may be used in any of the methods describedherein. For example, probes having different curvatures or lengths maybe used in any of these methods.

For example, in FIGS. 341A-341J, the elements shown in FIGS. 341A-341Fmay be used to deliver an IPD into the body. Elements shown in FIGS.341G-J may be used as adjuncts to the IPD system for accessing anddecompressing the foramen.

As mentioned, any appropriate guidewire may be used, particularly thoseincluding a tissue-penetrating distal end and a proximal end that isconfigured to releasably couple to the distal end of an implant ordevice (e.g., the IPD delivery device shown in FIG. 341F). FIGS. 341Cand 341H both illustrate pullwires or guidewires that are so adapted.For example, the distal end may include a lip or rim (e.g., a ball,cylinder, etc.) that may be coupled with a receiver on the device orimplant.

A sizer may be used to determine what size implant (e.g., IPD) isappropriate for use within the patient. Examples of sizers that may beused are illustrated in U.S. patent application Ser. No. 12/140,201(filed Jun. 16, 2008), now Publication No. US-2008-0312660-A1. Onevariation is shown in FIG. FD, and includes a distal end that couples tothe guidewire so that it can be pulled distally into the inner spinousspace (e.g., between the inferior and superior processes). Based on howfar it can be pulled into the space, the size of the opening, andtherefore an appropriately sized implant, may be determined.

In the IPD system shown in FIGS. 341A-341J, the IPD is attached to adelivery device shown in FIG. 341E. In this example, the IPD sits in aportion of the delivery device so that the delivery device may becoupled distally to the guidewire after it has been positioned andpulled in to place. The proximal end of the IPD delivery device isconfigured to extend out of the device, and may include a releasecontrol for releasing the IPD once it has been placed within the body(e.g., between the spinal processes as described below). For example,the IPD delivery device may include a wire or cable connecting theproximal end (elongate proximal region) and the distal end through theimplant (IPD). Triggering release of the IPD once it has been positionedwill release the distal end coupled to the guidewire/pullwire from theproximal end coupled to a proximal handle. Releasing the distal end mayallow it to be withdrawn from the body by pulling on theguidewire/pullwire (distally) and the rest of the IPD delivery devicemay be withdrawn proximally. The IPD implant is left behind in position.

The implant may then be secured in place. For example, FIG. 341Fillustrates an IPD locking device. The locking device includes one ormore expandable regions that either connects to the implant (IPD) tohold it into place, or they alter the shape of the implant to hold it inplace. In some variations, the device is self-locking. For example, thedevice may include a shape or structure that expands after beingimplanted, preventing it from dislodging or migrating. In somevariations one or more “locks” or anchors may be attached or extendedfrom the device to hold it in place.

FIGS. 342A-342J illustrate one variation of inserting an IPD to distracta patient's spine; FIGS. 342K-342R illustrate a method of decompressinga region of the spine that has been distracted after insertion of theIPD. In this example, the IPD is delivered through the inner spinousprocess ligament. For example, in FIG. 342A, the guide (shown here as anepidural needle) is inserted from outside of the patient to the innerspinous process ligament. In FIGS. 342A-342J, the spinal structuresillustrated resemble though shown in slightly more detail in FIGS. 339and 1. In FIG. 342B, a second probe (or portion of the probe) is thenextended coaxially from the first probe is extended through theligament. In this example, the inner probe cannula has atissue-penetrating tip that passes through and curves back dorsally, asshown. A sharpened guidewire may then be passed through the probe, asshown in FIG. 342C. FIG. 342D shows a top view of a portion of the probepassing between the spinous processes and through the inner spinousligament. The probe (inner and outer members) may then be removed,leaving the guidewire/pullwire extended through the ligament, as shownin FIGS. 342E and 342F. In this example, the guidewire extends bothdistally and proximally from a patient's body. The proximal end of theguidewire includes a coupling member 95507 for coupling to the distalend of a device, as described above. A distal handle 95505 may then beattached to the distal end of the guidewire, as shown. In somevariations, this distal handle 95505 includes a capture mechanism forcapturing the sharp distal end of the pullwire.

With the guidewire through the inner spinous process ligament, a sizer95509 can then pulled through with the distal handle, shown in FIG.342G. After sizing the distraction space, the appropriately sized IPDcan be inserted between the inner spinous processes using the IPDdelivery tool 95510, as shown in FIG. 342H. The IPD delivery tool 95510includes an IPD and is distally coupled to the proximal end of theguidewire, as shown pulling on the distal handle 95505 connected to theguidewire pulls the IPD in the delivery tool through the ligament untilit is positioned as desired (e.g., shown in FIG. 342I in top view),between the spinous processes and within the ligament. The IPD may bepositioned by bimanually manipulating the IPD delivery device. Forexample, the device may be pulled distally by pulling on the distalhandle, or proximally by pulling on the proximal end (handle) of the IPDdelivery device.

Once the IPD is in position, the IPD delivery device may be decoupledfrom the IPD, so that the distal region of the delivery device can bewithdrawn distally (by pulling on the guidewire) and the proximalportion can be withdrawn proximally, leaving the device in place. Insome variations, the IPD may be locked into position either before,after or during the removal of the IPD delivery device.

Alternatively, FIGS. 342J-342R illustrate an embodiment in which the IPDimplantation is used as part of a decompression procedure. In thisexample, the first guidewire remains attached to the IPD delivery deviceeven after the IPD has been positioned. For example, in FIG. 342J, theproximal handle of the IDP delivery device may be used as a guide fordelivering a probe to a different region of the spine. Thus, in thisconfiguration, the spinal decompression portion of the procedure may beperformed through the same patient entry point as the IPD (although theprobe may be delivered through a second entry point, as well). The probemay be passed through the body to the spine, into the epidural space,and out of the foramen, as illustrated in FIG. 342K, to achievetransforaminal access. Some means of determining the entry into theepidural space may be used (i.e. a syringe and loss of resistancetechnique). After the probe is positioned, the guidewire may be passedthrough the probe, as illustrated in FIG. 342K. Neural localization maybe used during the passing of the guide to confirm the guide is abovethe nerve root before passing the guide wire. The probe used to positionthe second guidewire may be a different probe than the one used toposition the first guidewire, or it may be the same probe.

After accessing the foramen and passing a second guide wire, both theIPD delivery and foraminal access systems may be removed, as shown inFIG. 342L. In this variation, a guidewire may be left behind in bothcases. In some variations a third guidewire may be passed through theIPD as the first guidewire (and the distal end of the IPD deliverydevice) is removed. For example, the IPD delivery device may include apassage or channel for a third guidewire delivery device; the distal endof the third guidewire may be releasably coupled to the inside of thedistal end of the IPD delivery device. As it is withdrawn from thepatient distally, the third guidewire is pulled through. Alternatively,in some variations the first guidewire remains in place as the IPDdelivery device is removed proximally (e.g., pulling the proximal end ofthe guidewire proximally through the IPD and proximally out of thepatient.

In the example, illustrated in FIG. 342M, the IPD is then locked in toposition. For example, the IPD may be laterally secured by lockingexpandable wings 95522, 95522′ in place on either side of the IPD. Thewings can be made from a preset shape memory material that expands afterplacing or stainless steel plastic that is cold worked duringinstallation, or non-expandable using solid metal or plastic. In somevariations, the device may be locked in place by extending one or moreanchoring structures (e.g., struts) from the IPD. The device may beanchored to or against the bone (spinous processes). FIG. 342Nillustrates the IPD laterally anchored into position by the expandablewings 95522, 95522′. In some variations, the anchors may be deployed bydeforming a portion of the IPD so that it secures the IPD (e.g., byexpansion) in position. In some variations, the IPD may include aninflatable region that may be filled (e.g., from a proximal port) with afiller, including bone cement or other materials.

Thereafter, the foramen may be decompressed as illustrated in FIGS. 342Oto 342R. For example, a tissue modification device may be pulled intothe spinal foramen using the second guidewire, as illustrated in FIG.342O. In this example, the distal handle is attached to the secondguidewire and used to pull a tissue modification device 95534. In thisexample, the tissue modification device includes a flexible distal endthat includes a tissue modifying surface (e.g., a sharp or bladedsurface) to remove tissue and thereby decompresses the foramen. Thetissue modification device may include tissue capture for removing cuttissue. The tissue modification device may also include a proximalhandle, allowing it to be manipulated proximally as well as distally,using the distal handle. In this example, the tissue modification devicemay be bimanually manipulated (moved back and forth proximally anddistally) to decompress the tissue, as shown in FIG. 342P. Meanwhile,the IPD remains anchored, distracting the spinous processes, asillustrated in FIG. 342Q. This distraction may enhance access to theforamen, and thereby enhance the decompression. Once the decompressionis complete, the tissue modification device 95534 may be removed, andthe decompression is completed as illustrated in FIG. 342R.

The method of distracting the processes and also of decompressing usingthis decompression may have many advantages over existing methods. Asdescribed above, the method (and variations of this method) allowspercutaneous delivery for both IPD and decompression systems. Asmentioned, however these methods and tools may also be used in an open(or partially open) procedure. In addition, the decompression anddistraction may be achieved through same percutaneous entry point, orthough different entry points.

One substantial advantage over existing methods of inserting the IPD anddistracting the bone is that the distraction device is inserted bypulling (either pulling distally or pulling both distally andproximally). Existing method require pushing, which may be moredifficult, particularly given curved or bent pathways through the body.In addition, pushing may require more force, and may also risk damagingsurrounding tissue. Pulling to distract the bone achieves a mechanicaladvantage in part because a long flexible taper may be included at thedistal end of the delivery device that is designed to allow it to maketight turns, allowing for straight posterior delivery.

In some variations, the distraction may be performed using an expandableor inflatable device that may be inserted either acutely or long-term.For example, an inflatable device may be pulled into position using theguidewire/pullwire as described above, and (once positioned) may beinflated or filled with a material, including a bone cement or othermaterial (bone chips, etc.). Once inflated, the delivery device may bedecoupled, leaving the inflated (“balloon” or fillable sleeve) in place.Alternatively, the device may be deflated/emptied and removed.

The methods described herein may also include visualization. Forexample, any of the steps described herein may include one or morevisualization steps. Indicators, including radioopaque,ultrasound-visible, or other markers may be included on any of thedevices described, including in particular the sizer and implant(s). Thebimanual methods described herein also allow tactile feedback. Forexample, tactile placement may be used to select the distraction sizeusing the spacer (to feel how wide/narrow the opening to be distractedis).

In addition to methods of implanting distracters and othertissue-modifying devices, the methods and systems described herein mayalso be used to position and implant, including anchoring other devices,including electrical leads.

Electrical leads may be used to treat pain, particularly limb pain thatis otherwise irresolvable. For example, a spinal cord stimulator, alsoknown as a dorsal column stimulator, may include one or more leads thatare implantable and used to treat chronic neurological pain. Oncepositioned within the body, the electrical lead may provide electricimpulses to alter the perception of pain. The lead is typicallyimplanted into the epidural space either by percutaneous approach or bysurgical laminectomy or laminotomy. A pulse generator or RF receiver maythen be implanted in the abdomen or buttocks, and a wire harnessconnects the lead to the pulse generator. For example, FIG. 343illustrates one example of a spinal cord stimulator system that may beused to treat pain.

One problem with existing leads used for pain management is thenecessary to ensure that the leads do not migrate substantially, and areplaced in the correct portion of the body (spine) for optimal treatment.The methods and systems described herein may be used to both positionand anchor a lead, and may allow anchoring of both the proximal anddistal end of the lead. For example, the methods described herein mayallow anchoring of the lead to the spinous processes, to the lamina,within the lateral recess, within the foramen, or the like, so that thelead can be positioned appropriately near a neural target such as aspinal ganglion, nerve root, etc. As mentioned, this anchoring may allowreduced risk of migration of the lead.

To place and anchor the stimulation lead, the system described above(e.g., in FIGS. 340A-340F) may be used to first position the guidewireadjacent to the implantation site. For example, one or more probes maybe used to position create a pathway from a proximal insertion siteadjacent to the target implantation site. A probe having an outercannula may be inserted near the target implantation site (e.g., near aspinal target such as the nerve root or ganglion), similar to the methoddescribed above for spinal decompression. FIG. 344 shows a schematic ofone potential pathway extending above a pedicle. The pathway allows thelead to be positioned near (adjacent to) a spinal ganglion, and past twoor more spinous processes to which it can be anchored proximally and/ordistally. Alternatively, the pathway may extend through the lateralrecess and/or foramen so that the lead can be secured within theforamen.

For example, a cannulated probe may be inserted through the foramen, sothat the distal end of the probe points towards an exit point out of thebody; a guidewire or pullwire having a sharp or tissue-penetratingdistal tip can then be inserted through the probe around the ganglion orother target nerve region, and out of the patient. The probe allows theguidewire/pullwire to pass into the subject and around the targetregion. When the guidewire/pullwire exits the probe, it continues toextend from the probe in a substantially straight pathway until itextends from the subject, forming a second (e.g., a distal) exit point.After the distal end of the guidewire/pullwire has exited the patient,it may be secured with a distal handle, as mentioned above, and theprobe may be removed.

In some variations, the position of the guidewire/pullwire may beconfirmed by using a neural localization device (as shown in FIG. 340C).In some variations, the neural localization device includes one or moreelectrodes that may be used to applying energy to stimulate nearbynerves; this stimulation can be detected when the neural localizationdevice is sufficiently near the target neural tissue.

FIG. 345 shows another pathway that may be used to position and/oranchor a stimulator lead. In FIG. 345 the guidewire is positioned up ordown the lateral recess from one lamina to another lamina. The lead maybe anchored to the lamina so that the lead can apply simulation to theappropriate region of the cauda equina. In this example the probe mayform a channel for the guidewire/pullwire that extends between andaround the lamina as indicated.

One the guidewire/pullwire has been positioned near the appropriatetarget, it may be used to pull the lead into position. FIG. 34026illustrates one variation of a lead that is adapted for pulling intoposition using a pullwire. Any appropriate lead may be used. Forexample, the lead may be a paddle lead, a round (or cylindrical) lead,or the like. In FIG. 34026, the lead includes a distal coupling region95901 configured to releasably couple to the proximal end of theguidewire/pullwire as mentioned above. FIG. 34026 shows the lead coupledto a guidewire 95905 at the distal end. At either end of the stimulationelectrode region 95903 (shown as band electrodes), are distal andproximal anchor regions 95907, 95907′. These anchor regions may includeanchors such as sharp hooks or prongs that may be extended from thelead. For example, a lead anchor may be a superelastic or shape memorymaterial that can be extended from the lead once it has been positioned.A control or release at the proximal end may control release of theanchor(s). In some variations the anchor region includes an expandableanchor, such as an inflatable or fillable member that may be expanded tosecure the lead at either or both ends. In some variations an expandablemember may be used to extend a hook or other anchor. In some variationsthe anchor regions include holes or openings through with an additionalanchor (e.g., screw, hook, etc.) may be positioned. Alternatively, thelead may include integrated screws that may be used to attach the lead.

The proximal end of the lead shown in FIG. 34026 includes a connector toan implantable pulse generator (IPG) that may be positioned elsewhere inthe body. The lead maybe secured proximally to a delivery portion thatmay be separated or detached from the lead once it is positioned and/oranchored. For example, a delivery portion may include an elongate memberhaving a control for controlling engagement of the anchors.

In operation, the lead may be positioned using bimanual manipulation(pulling from both the distal and proximal ends) to optimize theimplantation/insertion position. The lead may be activated during theimplantation procedure in order to determine which implantationlocations work best. Once an optimal position has been determined, theanchors securing the device in position (e.g., within the foramen,and/or to the pedicle(s) or lamina) may be engaged. The distal guidewirecan be detached and removed. In some variations, the distal anchor maybe activated (engaged) by detaching the guidewire/pullwire from thedistal end of the lead.

Also described herein are methods of treating or preparing one or morejoints. For example, the devices, systems and methods described hereinmay be used to resurface a joint, including resurfacing of cartilage andpreparation for fusion of the joint. For example, a probe may be used toinsert a guidewire between the sides or walls of a joint (e.g., a bonejoint). As before, the wire may extend from a first (proximal) sitethrough the body around and/or through the joint, and out of a second(distal) site of the body, allowing bimanual control. A tissuemodification device that is configured to resurface the joint may thenbe coupled to the distal end of the guidewire/pullwire and pulled intoposition within the joint and used to resurface the joint.

For example, in one variation, the methods and systems described hereininclude facet joint fusion methods and systems. A facet joint may befused by first accessing the joint, then preparing the joint andparticularly the joint surface(s) (e.g., by roughening or abrading). Thejoint may then be fixed using a support (e.g., a cage, etc.) or asettable material (bone cement) or graft material. In some variationsthe fixation step (which may be optional) may include pulling anexpandable or finable material into position and expanding and/orfilling it with material.

In one variation of a method for fusing a facet joint, a cannulatedprobe for guiding a guidewire/pullwire is first inserted in and/oraround the joint. FIG. 347A illustrates a facet joint 951005 includingthe superior and inferior surfaces between the lower 951009 and upper951007 vertebra. A guidewire/pullwire may be threaded through the facetjoint as indicated by the line 951003. In some variations, the pathwaythrough the facet joint passes over the top of the superior articulatingprocess (SAP). In some variations, the pathway through the facet jointpasses under the SAP giving access to the tip of the SAP. Placement ofthe guidewire around or through the facet joint may be aided bydistraction of the spinous process, as described above. Thus, in somevariations, the spinous process may be distracted before performing theprocedure. FIG. 347B shows another portion of a spine including a facetjoint 951011 that may be fused as described herein.

Once the probe has been used to position the guidewire, it may beremoved. As illustrated above, the probe may include one or a pluralityof (concentric) cannula including cannulas having different curvaturesso that the guidewire may be directed around the joint and pointedtoward the appropriate exit site. The guidewire or pullwire may then bepushed through the cannula and out of the patient. A distal handle maythen be attached to the distal end of the guidewire to aid inmanipulating the guidewire/pullwire from the distal end.

Next, a treatment device may be pulled into position in the joint bycoupling the distal end (or end region) of the joint treatment device tothe proximal end of the guidewire/pullwire. In some variations thetreatment device includes one or more surfaces that are configured toabrade, scratch or otherwise prepare the surface for the fusion. Forexample, FIGS. 348A-348E illustrate variations of a treatment device. InFIG. 348A, the treatment device includes a front and a back articulatingsurface that can be drawn across the joint surfaces to roughen them. Inthis example, the distal end of the device includes anattachment/connector site for the guidewire. The proximal end alsoincludes an elongate member and may have a proximal handle. In somevariations the roughening surface is expandable, so that it may bepulled into the joint in a collapsed or condensed form (protectingnon-target tissue), and once in the joint it can be expanded to thetreatment form. For example, the device may be inflatable; inflation mayexpand the device so that the contact surface(s) can push against thejoint surface(s). Once in position, the device can be moved bimanuallywithin the joint to scrape or otherwise modify the joint surfaces, bypulling distally and proximally (e.g., back and forth).

FIGS. 348B-348E illustrate alternative cross-sections for the jointtreatment devices described. For example, in FIG. 348B, the device issubstantially flat, having an upper and lower surface. As mentioned,this device may be inflatable/expandable to increase (or decrease) thespacing between the upper and lower surfaces, or to “stiffen” theimplant once it is expanded. FIG. 348C shows a device having an ovalcross-section, and FIG. 348D shows a device having a roundcross-section. In all of these variations the devices include ‘teeth’ orprotrusions that are configured to roughen the joint surface, which mayhelp with the fusion. In some variations the devices are configure toabrade, cut, and/or remove cartilage in the joint. In some variationsthe device is configured to abrade cartilage without substantiallycutting or removing bone. In some variations the device surface isconfigured to abrade cut and/or remove bone from the joint.

The device may be actuated by moving it backwards and forwards(proximally and distally), by bimanual reciprocation. In somevariations, such as that shown in FIG. 348E, for example, the device mayalso or alternatively be articulated by rotating it axially once it isin position in the joint.

In some variations the procedure for fusing the joint (e.g., facetjoint) may include the use of more than one facet joint treatmentdevices. For example, treatment devices having different profiles (e.g.,widths) may be used during the treatment. Alternatively, treatment mayinclude selectively removing some of the bone or other tissue from thejoint, which may be performed using the treatment device shown or usingadditional devices, including flexible bone biting devices such as theflexible ronguers described, for example in U.S. patent application Ser.No. 11/405,848, titled “Mechanical Tissue modification devices andmethods” (filed Apr. 17, 2006), now Publication No. US-2012-0078253-A9and herein incorporated by reference in its entirety. The sameguidewire/pullwire may be used with multiple devices, as each devicetypically includes a distal coupler for securely coupling to theproximal end of the guidewire/pullwire, allowing it to be articulatedwithin the joint.

Once the joint has been prepared using the device or devices, the devicemay be removed, and a support structure or material may be added to fusethe joint. The guidewire/pullwire may remain in position, so that it canbe used to pull in or apply the material. For example, in somevariations the pullwire may be used to position a cage or othermechanical support within the joint. The mechanical support may becoupled to the proximal end of the pullwire directly or indirectly(e.g., via an elongate carrier structure from which it can be releasedonce it is positioned), and pulled into position. In some variations thepullwire may be used to pull a tube or other fluid material deliverydevice into position in the joint, to apply a filer material such asbone cement, bone graft material, etc. In some variations, the pullwiremay be used to pull into position in the joint an expandable or finablestructure that will be implanted in the joint. For example, a mesh orporous “bag” structure may be pulled into position (and decoupled fromthe pullwire) and filled with appropriate fusing material (e.g., cement,etc.). In some variations a bag or balloon-like structure is pulled intoposition and filled.

As mentioned above, in any of the facet joint procedures describedherein, all or a portion of the facet (e.g., the superior and/orinferior spinous processes) may be cut. For example, a procedure forfusing or preparing a facet joint may include a facetectomy,particularly for TLIF (Transforaminal Lumbar Interbody Fusion)procedures. The procedure may include a facet joint treatment devicethat is configured to saw through bone. For example, the device mayinclude one or more cable-type saws including a distal end that isconfigured to couple to the pullwire as described above. As mentioned, aprobe or probes may be used to place the pullwire under the facet joint.A facet joint modifying device may then be pulled in under bimanualcontrol. Pulling the facet joint modifying device dorsally (e.g., bydistal/proximal reciprocation) would result in the removal of the entirefacet joint. This method may be faster than current methods whichinvolve slow biting with ronguer-type devices.

For example, FIG. 349A illustrates a cross-section through one variationof a facet-joint modifying device that includes two bone-sawing elements951202, 951202′. The two saw elements (which may be cables or surfacesincluding blades) may be separated by a spacer 951205. FIG. 349C shows atop view of one variation of a facet-joint modifying device configuredto perform a facetectomy. The distal end of the device is configured tocouple with the pullwire, as described above. The tissue-contactingportion of the device may include two parallel cutting surfaces (whichmay be cables) 951202, 951202′ that are separated from each other. Thesetwo separate cutting surfaces may allow two cuts to be made through thefacet joint simultaneously, permitting removal of a portion of the facetjoint. This version of the facet-joint modifying device may also includeone or more spacers 951205. Spacers may prevent the cutting surfacesfrom spreading or contracting towards each other, particularly if thecutting surfaces are cables. In some variations these spacers may beremovable or separating, so that as the facet joint modifying devicecuts the facet joint, pressure applied as that device is reciprocatedagainst the bone may cause separation, breaking, or removal of thespacer. FIG. 349B illustrates a cross-section through one portion of thedevice having a breakable (e.g., frangible) spacer 951205.

Other facet joint modifying devices (including those shown above inFIGS. 348A-348E) may include a single tissue-modifying surface, and thusdoes not need a spacer.

Also described herein are methods and systems for removing material froma body region, including removal of disc material. For example, thesystems and devices describe herein may be used to perform discectomyand/or remove or repair of disc herniation.

In disc treatments, a probe may be used to pass one or moreguidewire/pullwires through the disc so that the guidewire/pullwireextends proximally from a proximal exit site around or through a portionof the disc, and out of the patient at a second, distal site. Theguidewire is typically left in place while the probe may be removed.Once the guidewire/pullwire is in position, it may be used with one ormore disc treatment devices. Examples of treatment devices areillustrated in FIGS. 350A-350B. these exemplary disc treatment devicesare configured to be delivered relatively flexible into the disc region,but may be expanded or otherwise allowed to conform to a more rigid formonce within the disc region. In FIG. 350A the curved device includes aserrated edge. The device may be a ribbon of material (including metalmaterials) that is stiffer when curved slightly than when allowed to layflat. Another example of this variation is shown in FIG. 350B.

The systems and methods described herein may also be used as port of aPosterior Lumbar Interbody Fusion (PLIF) procedure. Unilateral posterioror posteriorlateral approaches to access the disc space can be lessinvasive than bilateral approaches but instrument and implantpositioning can be challenging. For example, it may be difficult tocompete a discectomy contralaterally and position a single TLIF cage orposterior disc replacement across the appropriate disc space, asillustrated in FIG. 351A. The endplates are heterogeneous, and thusmisplaced implants may not have the best contact with dense corticalbone 951401, placing them at greater risk for subsidence. To addressthis issue, a bimanually controlled pullwire system can be used to guideand pull instruments and implants into proper position in the discspace.

For example, FIGS. 351B and 351C illustrate one variation of a PLIF-typeprocedure that is made more effective using the pullwire techniquesdescribed herein. In FIG. 351B, for example, the guidewire/pullwire isfirst positioned in the disc space using a probe or probes, as describedabove. In one variation, a cannulated probe having a curved distal endis inserted contralaterally and percutaneously in to the disc space,toward an ipsilateral direction. The pullwire may then be passed throughthe probe and out of the disc on the ipsilateral side. As illustrated inFIG. 351B, the procedure may be combined with a TLIF procedure in whichpart of the ipsilateral facet joint has been removed.

The pullwire may then be placed through the probe and extended distallyout of the disc. In FIG. 351B, the pullwire extends distally from theipsilateral incision (the excised region). Once the pullwire is inposition, it may be used to pull one or more instruments or device(e.g., implants, cages, fillable/expandable structures, etc.) intoplace, as described above. In some variations a spacer or distractor maybe used to open the disc space, as illustrated in FIG. 351C.

In any of the variations described herein, the method may also includethe insertion of a pivot that may help guide the pullwire and/or devicespulled by the pullwire. For example, in FIG. 351C the distractor elementmay act as a pivot point to help control the ventral/dorsal location ofthe pullwire as it is manipulated. In this variation, the distractor isa pivot that is configured as a “rapid exchange” elongate element; thedistal end of the pivot is configured to couple with the pullwire sothat it can be pushed along the pullwire, yet still allow the pullwireto be pulled distally and proximally through or around the pivot. Insome variations the pivot includes a distal channel for the pullwire. Asillustrated in FIG. 351C, the pivot may be inserted from either theproximal or distal end of the pullwire (typically after it has beeninitially positioned using the probe) and slide along the pullwire untilit is positioned at the desired pivot point. Once in position, it may beheld in place (e.g., anchored) from within the body or from outside ofthe body (e.g., by a clamp or other anchor), or simply held in place. Inthe variation shown in FIG. 351C, the pivot is also a distractor, andthus may be used to separate tissues (e.g., bone). In other variationsthe pivot is anchored or anchorable in the body, and provides a surfaceagainst which the pullwire may move without allowing substantialmigration of the pullwire from the pathway through the body.

Access and Tissue Modification Systems and Methods

In general, the guidewire systems described herein includes a guidewireand at least one surgical device that are configured so that theproximal end of the guidewire couples to the distal end of theguidewire. The guidewire typically has a distal end that is configuredto extend from a subject's body and be manipulated, and a proximal endthat includes a coupling member for coupling to the surgical device. Thecoupling member may be referred to as a device coupling member and maybe located at or near the proximal end of the guidewire. Any appropriatesurgical device or devices may be included as part of the guidewiresystem. The surgical device typically includes a coupling member on ornear its distal end that is configured to mate with the coupling memberon or near the proximal end of the guidewire. The device-side couplingmember may be referred to as a guidewire coupling member.

Methods of using these systems, and particularly methods of quicklyexchanging surgical devices during a procedure, are described in greaterdetail below.

Various embodiments of a guidewire system and method for positioning oneor more surgical devices in a patient are provided. Although thefollowing description and accompanying drawing figures generally focuson positioning various surgical devices in a spine, in alternativeembodiments, guidewire systems and methods of the present invention maybe used to position any of a number of devices in other anatomicallocations in a patient's body.

Referring to FIG. 355, one embodiment of a guidewire system 35510 isshown coupled with a tissue cutting device 35511 in position within apatient's spine. Further description of various embodiments of cuttingdevice 35511 may be found in U.S. patent application Ser. No.11/461,740, entitled “Multi-Wire Tissue Cutter,” and filed Aug. 1, 2006,now Publication No. US-2008-0051812-A1, the full disclosure of which ishereby incorporated by reference. A number of alternative embodiments ofcutting devices, many of which may be used (or adapted for use) withguidewire system 35510, are further described in U.S. patent applicationSer. No. 11/375,265, entitled “Methods and Apparatus for TissueModification,” and filed Mar. 13, 2006, now U.S. Pat. No. 7,887,538;Ser. No. 11/405,848, entitled “Mechanical Tissue Modification Devicesand Methods,” and filed Apr. 17, 2006, now Publication No.US-2012-0078253-A9; Ser. No. 11/406,486, entitled “Powered TissueModification Devices and Methods,” and filed Apr. 17, 2006, now U.S.Pat. No. 7,938,830; and Ser. No. 11/429,377, entitled “Flexible TissueRasp,” and filed May 4, 2006, now U.S. Pat. No. 8,048,080. The fulldisclosures of all of the foregoing references are hereby incorporatedby reference.

As described in further detail in U.S. patent application Ser. No.11/461,740, now Publication No. US-2008-0051812-A1, tissue cuttingdevice 35511 may include a shaft 35512, a proximal handle 35516, aflexible distal portion 35513, two or more cutting blades 35526 and aguidewire coupling member 35530. Guidewire system 35510 may include aguidewire 35532 having a sharpened tip 35533 (often referred to hereinas the “sharpened distal tip”) for facilitating advancement of guidewire35532 through tissue. Optionally, guidewire 35532 may also include adevice coupling member that is configured as a shaped member (notvisible in FIG. 355) at the end opposite sharpened tip 35533 (oftenreferred to herein as the guidewire “proximal end”) for coupling withcoupling member 35530. Guidewire system 35510 may also include aguidewire handle 35534 (or “distal handle”) for coupling with guidewire35532, which in some cases may include a tightening member 35536 forsecuring a portion of guidewire 35532 within guidewire handle 35534.

In some embodiments, cutting device 35511 may be advanced into apatient's back through an incision 35520, which is shown in FIG. 355 asan open incision but which may be a minimally invasive or less invasiveincision in alternative embodiments. In some embodiments, device 35511may be advanced by coupling guidewire connector 35530 with guidewire35532 that has been advanced between target and non-target tissues, andthen pulling guidewire 35532 to pull device 35511 between the tissues.Various embodiments of such a method for delivering a device aredescribed in further detail below. Generally, guidewire system 35510 maybe used to pull flexible distal portion 35513 into place between tissuesin hard-to-reach or tortuous areas of the body, such as between a nerveroot (NR) and facet joint and through an intervertebral foramen (IF).Generally, flexible portion 35513 may be advanced to a position suchthat blades 35526 face tissue to be cut in a tissue removal procedure(“target tissue”) and a non-cutting surface (or surfaces) of flexibleportion 35513 faces non-target tissue, such as nerve and/orneurovascular tissue. In the embodiment shown in FIG. 355, blades 35526are positioned to cut ligamentum flavum (LF) and may also cuthypertrophied bone of the facet joint, such as the superior articularprocess (SAP). (Other anatomical structures depicted in FIG. 355 includethe vertebra (V) and cauda equina (CE)). In various alternativeembodiments, flexible portion 35513 may be replaced with a curved, rigidportion, a steerable portion, a straight portion with a distal extensionor the like. The configuration, dimensions, flexibility, steerability,materials and the like of flexible portion 35513 may be adjusted, inalternative embodiments, depending on a type of tissue or anatomicalstructure to be accessed or modified.

Before or after blades 35526 are located in a desired position,guidewire 35532 may be removably coupled with guidewire handle 35534,such as by passing guidewire 35532 through a central bore in handle35534 and moving tightening member 35536 to secure a portion ofguidewire 35532 within handle 35534. A physician (or two physicians orone physician and an assistant) may then pull on proximal handle 35516and distal handle 35534 to apply tensioning force to guidewire 35532 andcutting device 35511 and to urge the cutting portion of device 35511against ligamentum flavum (LF), superior articular process (SAP), orother tissue to be cut. Proximal handle 35516 may then be actuated, suchas by squeezing in the embodiment shown, to cause one or both blades35526 to move toward one another to cut tissue. Proximal handle 35516may be released and squeezed as many times as desired to remove adesired amount of tissue. When a desired amount of tissue has been cut,guidewire 35532 may be released from distal handle 35534, and cutterdevice 35511 and guidewire 35532 may be removed from the patient's back.

With reference now to FIGS. 356A-356I, one embodiment of a method foradvancing a tissue modifying device into a patient's body using aguidewire delivery system is shown. Although this method is shown inreference to placement of a device in a spine, in various alternativeembodiments, such a method may be used to place similar or alternativetissue modification devices in other locations in a human body, such asbetween tissues in a joint space, in the abdominal cavity, or in thecarpal tunnel of the wrist, between bone and soft tissue in other partsof the body, and the like.

Referring to FIG. 356A, in one embodiment of a method for advancing atissue modifying device, a probe 35640 may be inserted into a patient'sback using an open technique facilitated by retractors 35642. Targettissues of a procedure, in this embodiment, may include ligamentumflavum (LF) and/or facet joint (F) tissue of a vertebra (V), which mayimpinge on non-target tissues, such as nerve root (NR) and/or caudaequina (CE), of the lumbar spine. Also depicted in FIG. 356A is anintervertebral disc (D). In FIG. 356B, a curved distal portion of probe35640 has been advanced to a position between target ligamentum flavum(LF) and non-target nerve root (NR) tissues. As depicted in FIG. 356C,in some embodiments, a curved guide member 35646 may next be advancedout of an aperture on the curved distal portion of probe 35640. In oneembodiment, for example, guide member 35646 may be housed within probeand advanced out of the distal aperture by advancing a slide member35644 on the shaft of probe 35640. Next, as shown in FIG. 356D,guidewire 35632 may be advanced through guide member 35646 and out ofthe patient's back, using sharpened tip 35633 to facilitate passagethrough the patient's back tissue. Probe 35640 may then be removed, asshown in FIG. 356E, leaving guidewire 35632 in place between the targetand non-target tissues, as shown in FIG. 356F. Also shown in FIG. 356Fis a shaped member 35650 (in this embodiment, a ball) on the proximalend of guidewire 35632.

Further description of methods, devices and systems for advancing aguidewire between tissues using a probe are provided in U.S. patentapplication Ser. No. 11/429,377, entitled “Spinal Access and NeuralLocalization,” and filed on Jul. 13, 2006, now U.S. Pat. No. 8,048,080,the full disclosure of which is hereby incorporated by reference. Asdescribed in that reference, in some embodiments, the curved distalportion of probe 35640, curved guide member 35646, or both may includeone, two or more electrodes to help locate nerve tissue before placingguidewire 35632. Such neural localization helps ensure that guidewire35632 is positioned between target and non-target tissue, which in turnhelps ensure that a tissue modification device (or devices) placed usingguidewire 35632 are oriented so that a tissue modifying portion (orportions) of the device face and act on target tissue and not onnon-target tissue such as neural tissue.

Referring now to FIG. 356G, once guidewire 35632 is positioned betweentissues, its proximal end with shaped member 35650 may be coupled with acoupling member (i.e., guidewire coupling member 35662) on a distal endof a tissue modification device 35652. Tissue modification device 35652,in one embodiment, may include a proximal handle 35654, a rigid proximalshaft portion 35656, a flexible distal shaft portion 35658, tissuecutting blades 35660, and coupling member 35662. Coupling member 35662,various embodiments of which are described in greater detail below, maybe either attached to or formed in distal shaft portion 35658. In someembodiments, such as the one depicted in FIG. 356G, to attach guidewire35632 to coupling member 35662, guidewire 35632 may be laid into achannel on coupling member 35662, and guidewire 35632 and/or distalportion 35658 may be rotated, relative to one another, to lock shapedmember 35650 into coupling member. Various alternative embodiments forcoupling guidewires 35632 with coupling members 35662 are described ingreater detail below. Before, after or during coupling of guidewire35632 and tissue modification device 35652, guidewire 35632 may also becoupled with distal guidewire handle 35634, such as by advancing distalhandle 35634 over guidewire 35632 (solid-tipped arrow).

As depicted in FIG. 356H, tightening member 35636 may next be moved(curved, solid-tipped arrow) to tighten distal handle 35634 aroundguidewire 35632. Distal handle 35634 may then be pulled (straight,solid-tipped arrow) to pull guidewire 35632 and thus advance distalshaft portion 35658 of tissue modification device 35652 into placebetween target and non-target tissues in the spine, as shown in FIG.356I. Once device 35652 is positioned as desired, as depicted in FIG.356I, proximal handle 35654 and distal handle 35634 may be pulled(straight, solid-tipped arrows), to apply tensioning force to guidewire35632 and device 35652 and thus urge flexible portion 35658 and blades35660 against target tissue, such as ligamentum flavum (LF) and/or facetjoint (F) tissue. Handle 35654 may then be actuated (curved,double-tipped arrow) to cause blades 35660 to cut target tissue. When adesired amount of tissue is cut, guidewire 35632 may be released fromdistal handle 35634, and tissue modification device 35652 and guidewire35632 may be removed from the patient's back. Alternatively, theguidewire may be left at least partially in the body so that it can beused to position and/or actuate other surgical device. This method foradvancing tissue modification device 35652 using guidewire 35632 is butone exemplary embodiment.

Various aspects of the method embodiment just described, such as thenumber or order of steps, may be changed without departing from thescope of the invention. Furthermore, a number of alternative embodimentsof various devices and device elements are described below, which may beused in various embodiments of such a method. For example, in onealternative embodiment (not shown), probe 35640 and tissue modificationdevice 35652 may be combined into one device. Such a device may includea guidewire lumen through which guidewire 35632 may be passed. Thecombined device may be partially inserted into a patient, and guidewire35632 advanced between target and non-target tissues through theguidewire lumen. Shaped member 35650 (device coupling member) ofguidewire 35632 may then catch on one or more coupling members 35662 ofthe combined device (guidewire coupling member), to allow the device tobe pulled into position between the target and non-target tissues.Guidewire 35632 may then further be used to help apply tensioning forceto the device to urge an active portion against target tissues. Inanother alternative embodiment, access to the intervertebral foramen maybe achieved using a lateral approach, rather than a medial approach.These are but two examples of many alternative embodiments, and a numberof other alternatives are contemplated.

With reference now to FIG. 357, guidewire system 35710 is shown with analternative embodiment including a tissue modification device 35764,which may include a proximal handle 35766, a rigid proximal shaftportion 35768, and a distal flexible shaft portion 35770. Multipleabrasive members 35772 and a guidewire coupling member 35774 may becoupled with one side of flexible shaft portion 35770. In thisembodiment, guidewire 35732 may be coupled with coupling member 35774and used to pull distal shaft portion 35770 of modification device 35764into place between target and non-target tissues. Proximal handle 35766and distal handle 35734 may then be pulled/tensioned (solid-tippedarrows) to urge abrasive members 35772 against the target tissue, andhandles 35766, 35734 may further be used to reciprocate device 35764 andguidewire 35732 back and forth (hollow/double-tipped arrows) to modifythe target tissue. Reciprocation and tensioning may be continued until adesired amount of tissue is removed, at which point guidewire 35732 maybe released from distal handle 35734, and device 35764 and guidewire35732 may be removed from the patient's back. In various embodiments,tissue modification device 35764 may include any of a number of abrasivemembers 35772, abrasive materials, or the like, which may be arrayedalong distal shaft portion 35770 for any desired length and in anydesired configuration. Further examples of abrasive members 35770,materials, surfaces and the like are described in U.S. patentapplication Ser. No. 11/429,377, now U.S. Pat. No. 8,048,080, which waspreviously incorporated by reference. In various alternativeembodiments, shaft portions 35768, 35770 may both be rigid or may bothbe flexible and may have different cross-sectional shapes or the sameshape.

Referring to FIG. 358, in another alternative embodiment, an ultrasoundtissue modification device 35876 may be advanced into position in apatient's back using guidewire system 35810. In one embodiment, forexample, ultrasound device 35876 may include a proximal handle 35878, ahollow shaft 35880 having a distal window 35881, multiple ultrasoundwires 35882 extending through shaft 35880 and into window 35881, aguidewire connector 35884 coupled with a tapered distal end of shaft35880, an ultrasound generator 35888, and a wire 35886 coupling handle35878 with generator 35888. Handle 35878 may include, for example, anultrasound transducer, horn and/or other ultrasound transmissioncomponents. Shaft 35880 may be completely rigid, completely flexible, orpart rigid/part flexible, according to various embodiments. Ultrasoundenergy provided by generator 35888 may be converted in handle 35878 toreciprocating motion of wires 35882, and reciprocating wires 35882 maybe used to cut, chisel or otherwise modify soft and/or hard tissues.Further description of such an embodiment is provided in U.S. patentapplication Ser. No. 11/461,740, now Publication No. US-2008-0051812-A1,which was previously incorporated by reference. Guidewire connector 84may comprise one of a number of different connectors, variousembodiments of which are described in further detail below.

In another embodiment, and with reference now to FIG. 359A, guidewiresystem 35910 may be used to pull/advance a tissue access device 35990into place between target and non-target tissues. Tissue access device35990, for example, may include a proximal handle 35992, a hollow shaft35994 having a distal curved portion with a distal window 35996, and aguidewire connector 35998 coupled with a tapered distal end of shaft35994. As with previously described embodiments, shaft 35994 may beflexible along its entire length, rigid along its entire length, orrigid in part and flexible in part, and may be made of any suitablematerial or combination of materials. In some embodiments, shaft 35994may also be steerable, such as with one or more pull wires or othersteering mechanisms, for example to steer or curve a distal portion ofshaft 35994.

Once access device 35990 is in a desired position, with window 35996facing target tissue (such as ligamentum flavum and/or facet joint bonein the spine) and an atraumatic surface of shaft 35994 facing non-targettissue, any of a number of compatible tissue modification devices359100, 359101, 359104 or other devices may be advanced through accessdevice 35990 to perform a tissue modification procedure or otherfunctions. Such devices may swappable in and out of access device 35990and may be in the form of cartridges, so that various cartridges may beinserted and removed as desired, over the course of a procedure.Examples of several tissue modification devices are shown in FIG. 359A,including a rongeur device 359100, an ultrasound device 359101(including wire 359102 and ultrasound generator 359103), and anabrasive, reciprocating device 359104. Further examples of tissuemodification and other devices are described below with reference toFIGS. 359B-359M.

In one embodiment, for example, at least a distal portion of each tissuemodification device 359100, 359101, 359104 may be flexible, and aproximal portion of each modification device 359100, 359101, 359104 mayhave a locking feature for locking into proximal handle 35992 of accessdevice 35990. Thus, a given modification device, such as abrasive device359104, may be advanced into handle 35992 and shaft 35994, so thatabrasive members 359105 of device 359104 are exposed through window35996 and locking feature 35999 of device couples and locks withinhandle 35992. A user may then grasp handles 35934 and 35992, pull up tourge abrasive members 359105 against target tissue, and reciprocateaccess device 35990 and guidewire system 35910 back and forth to removetarget tissue. The user may then choose to remove abrasive device 359104and insert one of the other devices 359100, 359101 to further modifytarget tissues.

In various embodiments, any of a number of tissue modification devicesand/or other devices may be provided (for example as cartridges) forused with access device 35990. In some embodiments, one or more of suchdevices may be provided with access device 35990 and guidewire device35910 as a system or kit. Any given tissue modification device may acton tissue in a number of different ways, such as by cutting, ablating,dissecting, repairing, reducing blood flow in, shrinking, shaving,burring, biting, remodeling, biopsying, debriding, lysing, debulking,sanding, filing, planing, heating, cooling, vaporizing, delivering adrug to, and/or retracting target tissue. Non-tissue-modifying devicesor cartridges may additionally or alternatively be provided, such as butnot limited to devices for: capturing, storing and/or removing tissue;delivering a material such as bone wax or a pharmacologic agent such asthrombin, NSAID, local anesthetic or opioid; delivering an implant;placing a rivet, staple or similar device for retracting tissue;delivering a tissue dressing; cooling or freezing tissue for analgesiaor to change the tissue's modulus of elasticity to facilitate tissuemodification; visualizing tissue; and/or diagnosing, such as by usingultrasound, MRI, reflectance spectroscopy or the like. In given method,system or kit, any combination of tissue modification and/ornon-tissue-modifying devices may be used with access device 35990.

Although the example provided above describes the use of any of a numberof tissue modification devices and/or other devices for used with anaccess device 35990, these devices (also referred to as surgicaldevices) may also be used without an access device 35990. For example,as illustrated in FIGS. 356 and 357, a surgical device may be coupled toa guidewire and inserted (via a percuateous or open route) into apatient using the guidewire without the use of an additional accessdevice 35990. In some variations, particularly those in which theinternal spacing between target and non-target tissues is narrow orsmall, it may be better to use such devices without the additionalthickness of an access device 35990. Thus, in some variations, thesurgical devices used as part of the guidewire systems have a relativelyflat and flexible distal end region.

With reference now to FIGS. 359B-359M, distal portions of a number ofexemplary embodiments of surgical devices (which may be in cartridgeform in some embodiments and may be used with access device 35990) areshown. FIG. 359B shows a device 359430 including a sharpened, pointed,double-beveled distal tip 359432. Tip 359432 may be advanced acrosswindow 35996 of access device 35990 to cut tissue. FIG. 359C shows adevice 359440 including a diagonal-edge distal cutting tip 359442, whichmay be used in a similar manner to cut tissue. FIG. 359D shows a device359450 including multiple volcano-shaped abrasive members 359452. Inalternative embodiments of abrasive devices, any suitable abrasivemembers or surfaces may be used. FIG. 359E, for example, shows a device359460 including a portion of a Gigli saw 359462 attached to thedevice's upper surface, such as by welding. Any of a number of bladesmay alternatively be attached to a device, such as in the device 359470shown in FIG. 359F. Here, device 359470 includes a proximally placedblade 359472 having a cutting edge 359474, which may be advanced acrosswindow 35996 to cut tissue. FIG. 359G shows an alternative embodiment inwhich a device 359480 includes a distally placed blade 359482 with acutting edge 359484 that may be drawn back/retracted across window 35996to cut tissue. In another tissue-modifying embodiment, FIG. 359H shows adevice 359490 including a radiofrequency (RF) loop electrode 359492 forcutting tissue and extending proximally via two insulated wires 359494.

With reference to FIG. 359I, in an alternative embodiment, a device359500 may include a side-facing aperture 359502 and a chamber 359504.Device 359500 may be advanced into access device 35990 to align aperture359502 with window 35996 and may then be used to collect tissue inchamber 359504. Device 359500 may then be removed (in some variationsthrough access device 35990) to remove the tissue from the patient. Thismay be repeated as many times as desired, to remove cut tissue from thepatient. FIG. 359J shows a device 359510 having a clamp 359512 fordelivering an implant 359514. Implant 359514, for example, may be aposterior decompression implant such as the “X-STOP” InterspinousProcess Decompression™ devices offered by St. Francis MedicalTechnologies, Inc. (Alameda, Calif.), a foraminal implant such as thatdescribed in PCT Patent Application Pub. No. WO 2006/042206A2, or anyother suitable implant for the spine or other area of the body. FIG.359K shows an embodiment of a device 359520 used for delivering a rivet(or “tissue anchor”) 359524 through a distal aperture 359522. In oneembodiment, for example, tissue anchor 359524 may be anchored to boneand used to retract ligamentum flavum tissue to increase the area of aspace in the spine. Such a device is described in more detail, forexample in U.S. patent application Ser. No. 11/250,332, entitled“Devices and Methods for Selective Surgical Removal of Tissue,” andfiled Oct. 15, 2004, now U.S. Pat. No. 7,738,968, the full disclosure ofwhich is hereby incorporated by reference.

In another embodiment, and with reference to FIG. 359L, a visualizationdevice 359530 having a visualization element 359532 may be used withaccess device 35990. Such a device may include, for example, anendoscope, fiber optics, a camera coupled with a catheter or the like.In other embodiments, ultrasound, MRI, spectroscopy or other diagnosticor visualization devices may be used. FIG. 359M shows an alternativeembodiment of a device 359540, which includes a distal aperture 359542through which a tissue dressing 359544 may be delivered. Tissue dressing359544, for example, may include one or more fabrics, gel foam or thelike. In some embodiments, one or more pharmacologic agents may bedelivered through device 359540. Alternatively or additionally,irrigation and/or suction may be provided through device 359540. Asshould be apparent from the foregoing description, any suitable device,cartridge or combination of devices/cartridges may be used either withaccess device 35990 or without a separate access device. These devicesmay be positioned and/or manipulated (e.g., urged against a targettissue) using the guidewire systems described herein. In addition,multiple devices may be exchanged during a procedure using the sameguidewire.

Referring now to FIG. 360, another embodiment of a tissue access device360106, which may be advanced to a position in a patient's back usingguidewire system 36010, is shown. Tissue access device 360106 mayinclude, for example, a proximal handle 360107 having a hollow bore360108 and an actuator 360109, a hollow shaft 360110 extending fromproximal handle 360107 and having a distal curved portion and a distalwindow 360112, and a guidewire coupling member 360114 coupled with atapered distal end of shaft 360110. As with the previously describedembodiment, a number of different tissue modification devices 360116,360117, 360120 may be inserted and removed from access device 360106 toperform a tissue modification procedure, such as a rongeur 360116, anultrasound device 360117 (including a wire 360118 and generator 360119),and an abrasive device 360120. In the embodiment of FIG. 360, however,handle 360107 includes the additional feature of actuator 360109, whichmay be used to activate one or more tissue modifying members of varioustissue modification devices. For example, rongeur 360116 may be advancedinto hollow bore 360108 and shaft 360110, to position blades 360121 ofrongeur 360116 so as to be exposed through window 360112, and to lock alocking member 360115 of rongeur 360116 within handle 360107. Actuator360109 may then be moved back and forth (by squeezing and releasing, inthe embodiment shown) to move one or both blades 360121 back and forthto cut target tissue. Optionally, rongeur 360116 may then be removedfrom access device 360106 and a different modification device 360117,360120 inserted to further modify target tissue. Actuator 360109 may beused with some modification devices and not others. Again, in someembodiments, access device 360106, guidewire system 36010 and one ormore modification devices 360116, 360117, 360120 may be provided as asystem or kit.

With reference now to FIG. 361, a perspective view of one embodiment ofa tissue access device 361240 is shown. Device 361240 may include anelongate, hollow shaft 361242 having a distal aperture 361244, a distalextension 361246 (or “platform” or “tissue shield”) extending beyondshaft 361242, and a guidewire coupling member 361250 attached to distalextension 361246 for coupling with a guidewire 361252. Both shaft 361242and distal extension 361246 may be either rigid or flexible, in variousembodiments. In the embodiment shown, distal extension 361246 includesmultiple flexibility slits 361248 to enhance flexibility of that portionof device 361240. Shaft 361242, distal extension 361246 and guidewirecoupling member 361250 may be made of any suitable material (ormaterials), and may be made from one piece of material as a singleextrusion or from separate pieces attached together, in alternativeembodiments. Suitable materials include, for example, metals, polymers,ceramics, or composites thereof. Suitable metals may include, but arenot limited to, stainless steel, nickel-titanium alloy, tungsten carbidealloy, or cobalt-chromium alloy, for example, Elgiloy™ (Elgin SpecialtyMetals, Elgin, Ill., USA), Conichrome™ (Carpenter Technology, Reading,Pa., USA), or Phynox™ (Imphy SA, Paris, France). Suitable polymersinclude, but are not limited to, nylon, polyester, Dacron™,polyethylene, acetal, Delrin™ (DuPont, Wilmington, Del.), polycarbonate,nylon, polyetheretherketone (PEEK), and polyetherketoneketone (PEKK).Ceramics may include, but are not limited to, aluminas, zirconias, andcarbides.

In addition to various materials, tissue access device 361240 may haveany desired combination of dimensions and shapes. In some embodiments,for example, shaft 361242 and distal extension 361246 have differentcross-sectional shapes, while in other embodiments, they may have thesame cross-sectional shape. Some embodiments may include additionalfeatures, such as a mechanism for changing distal extension 361246 froma straight configuration to a curved configuration (such as with one ormore pull wires).

Any of a number of different surgical/tissue modification devices, suchas but not limited to those described in reference to FIGS. 359 and 360,may be used in conjunction with tissue access device 361240. Such atissue modification device may be used, for example, by passing thedevice through shaft 361242, such that a portion of the device extendsout of aperture 361244 to perform a procedure, while distal extension361246 protects non-target tissue from harm. In various embodiments,multiple surgical devices may be passed through and used with tissueaccess device 361240, either serially or simultaneously, depending onthe configuration of access device 361240 and the constraints of theoperating field and anatomy.

Referring to FIG. 362, in another embodiment, a tissue access device362260 includes an elongate, hollow shaft 362262, a handle 362264, adistal aperture 362266, and a distal extension 362270 having flexibilityslits 362268 and coupled with a guidewire coupling member 362272, whichmay be coupled with a guidewire 362274. This embodiment of tissue accessdevice 362260 is similar to the one described immediately above butincludes the additional feature of handle 362264, which in someembodiments may be used to actuate one or more surgical/tissuemodification devices passed through access device 362260.

FIG. 363 depicts another alternative embodiment of a tissue accessdevice 363280, including a proximal shaft portion 363282, a distal shaftportion 363286, and a handle 363284. Distal shaft portion 363286includes a window 363288, through which a portion of a surgical/tissuemodification device may be exposed to perform a procedure, and aguidewire coupling member 363290, which may be coupled with a guidewire363292. As with the previously described embodiments, any of a number ofsurgical devices may be passed through and used with tissue accessdevice 363280, according to various embodiments. Tissue modifyingportions of such devices may be exposed through or may even extend outof window 363288 to perform any of a number of procedures, while distalshaft portion 363286 otherwise protects non-target tissue from damage.In various embodiments, shaft portions 363282, 363286 may both beflexible, both be rigid, or one may be flexible and the other rigid. Inone embodiment, for example, shaft 363282, 363286 may comprise aflexible catheter, while in an alternative embodiment, shaft 363282,363286 may comprise a rigid, probe-like structure.

Any of the embodiments described in FIGS. 361-363 may further optionallyinclude one or more external support devices, which removably attach toshaft 361242, 362262, 363282 and one or more stabilizing structuresoutside the patient, such as a retractor, bed rail, or the like. Suchsupport devices, such as detachable support arms, may be provided with atissue access device 361240, 362260, 363280 as part of a system or kitand may be used to help support/stabilize the access device during use.

Coupling Members

As mentioned, in general, a coupling member on (or near) the proximalend of a guidewire mates with the coupling member on (or near) thedistal end of a surgical device. The coupling members may becomplimentary; for example, the device coupling member on the guidewiremay be received by a guidewire coupling member on the device. Couplingmembers may be configured to lock securely together. Coupling membersmay be configured so that reasonably high pulling forces (e.g., pullingon the distal end of the guidewire and/or the proximal end of thesurgical device) can be handled without breaking or de-coupling thecoupling members. In some variations the coupling members are configuredto lock together permanently or temporarily. For example, a couplingmember may be configured to secure together until adequate force isapplied to separate them.

With reference now to FIGS. 364A-364D, one embodiment of a surgicaldevice distal portion 364138 with a guidewire coupling member 364130 isshown in conjunction with a shaped guidewire 364134. Guidewire couplingmember 364130 may generally include a slit 364131 and a bore 364132.Guidewire 364134 may include a device coupling member formed as a shapedmember 364136 at one end, which is shown as a ball-shaped member 364136but may have any of a number of suitable shapes in alternativeembodiments. Generally, guidewire 364134 and shaped member 364136 may bemade of any suitable material, such as but not limited to any of anumber of metals, polymers, ceramics, or composites thereof. Suitablemetals, for example, may include but are not limited to stainless steel,nickel-titanium alloy, tungsten carbide alloy, or cobalt-chromium alloy,for example, Elgiloy™ (Elgin Specialty Metals, Elgin, Ill., USA),Conichrome™ (Carpenter Technology, Reading, Pa., USA), or Phynox™ (ImphySA, Paris, France). Suitable polymers include but are not limited tonylon, polyester, Dacron™, polyethylene, acetal, Delrin™ (DuPont,Wilmington, Del.), polycarbonate, nylon, polyetheretherketone (PEEK),and polyetherketoneketone (PEKK). Ceramics may include but are notlimited to aluminas, zirconias, and carbides. Shaped member 364136 maybe formed by attaching a separate member to one end of guidewire 364134,such as by welding, or may be formed out of the guidewire materialitself.

In the embodiment shown, guidewire 364134 may be coupled with couplingmember 364130 by first placing guidewire 364134 through slit 364131 intobore 364132, as shown in perspective view FIG. 364A and top view FIG.364C. Guidewire 364134 may then be pulled through bore 364132(solid-tipped arrows in FIGS. 364A and 364C), to pull shaped member364136 into bore 364132, as shown in perspective view FIG. 364B and topview FIG. 364D. As visible in FIGS. 364B and 364D, bore 364132 may betapered, so that shaped member 364136 may enter bore 364132 but may onlytravel partway through before reaching a diameter of bore 364132 throughwhich it cannot pass. In an alternative embodiment, bore 364132 mayinclude a hard stop rather than a taper. In any case, shaped member364136 may be pulled into bore 364132 to cause it to lodge there, andadditional pulling or tensioning force may be applied to guidewire364134 without risk of pulling shaped member 364136 farther through bore364132. Guidewire 364134 may thus be used to pull surgical device 364138through tissue and into a desired position for performing a procedure,and may further be used to apply tensioning/pulling force to surgicaldevice 364138 to help urge a tissue modifying portion of device 364138against target tissues.

As with many of the embodiments described previously and hereafter,guidewire coupling member 364130 may be either attached to or formed asan integral part of surgical device distal portion 364138, according tovarious embodiments. Coupling member 364130 may be made of any suitablematerial, as has been mentioned previously, and may have any desireddimensions and any of a number of different configurations, some ofwhich are described in further detail below. In various embodiments,coupling member 364130 may be attached to an extreme distal end ofsurgical device 364138 or may be positioned at or near the extremedistal end. Although coupling member 364130 is typically attached to orextending from a top or upper surface of surgical device 364138, in someembodiments it may alternatively be positioned on a bottom/lower surfaceor other surface.

In another embodiment, and with reference now to FIGS. 365A and 365B, aguidewire coupling member 365140 including a slit 365142 with one ormore curves 365144 and a bore 365143 may be attached to a surgicaldevice distal portion 365148. A guidewire 365146 having a cylindricalshaped member 365147 at one end may be placed through slit 365142 intobore 365143 and pulled distally (solid-tipped arrow), as shown in FIG.365A. When shaped member 365147 is pulled into bore 365143, it isstopped by, and cannot pass through, curves 365144, thus allowingguidewire 365146 to be used to pull device 365148 into place betweentarget and non-target tissues and apply tensioning force.

Referring to FIGS. 366A-366F, an alternative embodiment of a guidewirecoupling member 366150 is shown with a shaped guidewire 366158.Guidewire coupling member 366150 may include a transverse slit 366152,an axial channel 366154 and a transverse bore 366156. FIG. 366E shows afront perspective view of coupling member 366150, where member 366150would be mounted on a surgical device such that a front side 366151would face distally and a back side 366153 would face proximally. FIG.366F shows a rear perspective view of coupling member 366150 with backside 366153 and front side 366151.

FIG. 366A is a rear/left perspective view, and FIG. 366B is a top view,both showing guidewire 366158 with a ball-shaped member 366159 beingplaced through transverse slit 366152 into channel 366154. Channel366154 is generally an open portion within coupling member 366150,having a diameter similar to or the same as that of slit 366152, toallow guidewire 366158 to be rotated through coupling member 366150, asdepicted by the solid-tipped, curved arrow in FIGS. 366A and 366B. Bore366159 is sized to allow ball-shaped member 366159 (forming the devicecoupling member of the guidewire) to travel into it to rest withincoupling member 366150, as shown in FIGS. 366C and 366D. Ball-shapedmember 366159 is sized such that, when shaped guidewire 366158 isrotated into position within coupling member 366150, it cannot travelthrough channel 366154, and is thus trapped within bore 366156.Guidewire 366158 may thus be pulled, to pull a device into positionand/or to apply tension to the device, without guidewire 366158 pullingout of coupling member 366150. Guidewire 366158 may be disengaged fromcoupling member 366150 by rotating guidewire 366158, coupling member366150 or both, to release shaped member 366159 from bore 366156. In oneembodiment, coupling member 366150 may be attached to a top surface of adistal portion of a surgical device, such as by welding, adhesive orother attachment means.

An alternative embodiment of a guidewire coupling member 367160 isdepicted in FIGS. 367A-367E. In this embodiment, guidewire couplingmember 367160 includes a channel 367162, a central bore 367164 and aside channel, as shown in perspective view FIG. 367A, top view FIG. 367Band side view FIG. 367C. Channel 367162 is generally shaped and sized toallow a shaped member 367169 of a guidewire 367168 to passlongitudinally therethrough. Central bore 367164 is shaped and sized toallow shaped member 367169 to rotate within bore 367164. Side channel367166 is shaped and sized to allow guidewire 367168 to passtherethrough when guidewire 367168 is rotated about an axis throughshaped member 367169. An angle 367165 formed by channel 367162 and anopposite end of side channel 367166 may be any desired angle, in variousembodiments. For example, the angle in the embodiment shown (best seenin FIGS. 367B, 367D and 367E) is approximately 90 degrees. Inalternative embodiments, the angle could instead be less than 90 degreesor greater than 90 degrees. In one embodiment, for example, an angle ofabout 135 degrees may be used, while in another embodiment, an angle ofabout 180 degrees may be used.

As depicted in FIG. 367D, shaped member 367169 of guidewire 367168 maybe passed through channel 367162 and into central bore 367164(hollow-tipped arrow). Guidewire 367168 may then be rotated about anaxis approximately through shaped member 367169 (solid-tipped, curvedarrow). When rotated, guidewire 367168 passes through side channel367166 to its end, as shown in FIG. 367E. Guidewire 367168 may then bepulled, to pull a device attached to coupling member 367160 to a desiredposition in a patient's body, such as between target and non-targettissues. Rotated shaped member 367169 is trapped within central bore367164, due to its shape and size, and cannot pass into either sidechannel 367166 or channel 367162. To remove guidewire 367168 fromcoupling member 367160, guidewire 367168 may be rotated back to theposition shown in FIG. 367D and withdrawn from coupling member 367160through channel 367162.

Referring now to FIGS. 368A-368D, another alternative embodiment of aguidewire coupling member 368170 is shown. FIGS. 368A and 368B are frontperspective and rear perspective views, respectively, in which a channel368172 and a side channel 368174 of coupling member 368170 may be seen.FIGS. 368C and 368D are top views, showing coupling member 368170 withan inserted guidewire 368178. As seen in FIG. 368C, guidewire 368178with a shaped distal member 368179 may be advanced through channel368172 (hollow-tipped arrow), to position shaped member 368179 in acentral bore 368176 of coupling member 368170. Guidewire 368178 may thenbe rotated through side channel 368174 about an axis approximately aboutshaped member 368179 (solid-tipped, curved arrow). As shown in FIG.368D, guidewire 368178 may be rotated until it hits an end 368175 ofside channel 368174. Guidewire 368178 may then be pulled to pull adevice attached to coupling member 368170, as shaped member 368179 willbe trapped within central bore 368176, due to its shape and size. Whendesired, guidewire 368178 may be removed from coupling member 368170 byrotating guidewire 368178 back to the position shown in FIG. 368C andwithdrawing it through channel 368172. Channel 368172 may be located atany desired angle, relative to end 368175 of side channel 368174. In theembodiment shown, for example, the angle is approximately 135 degrees.As in the embodiment described immediately above, channel 368172 isgenerally shaped and sized to allow shaped member 368179 to passlongitudinally therethrough, central bore 368176 is shaped and sized toallow shaped member 368179 to rotate within bore 368176, and sidechannel 368174 is shaped and sized to allow guidewire 368178 to passtherethrough when guidewire 368178 is rotated.

Turning to FIGS. 369A and 369B, in another alternative embodiment, aguidewire coupling member may include a cam 369300 and a stationaryportion 369306 (only a part of which is shown). Cam may 369300 rotateabout an axis 369302 from an open position (FIG. 369A), which allows aguidewire 369304 to pass through, to a closed position (FIG. 369B),which traps guidewire 369304 against stationary portion 369306. In oneembodiment, cam 369300 may automatically move from open to closedpositions as guidewire 369304 is advanced (arrow in FIG. 369A) and maymove from closed to open positions as guidewire 369304 is retracted.Some embodiments of a coupling member, such as that shown in FIGS. 369Aand 369B, may be used with a guidewire 304 that does not have a shapedmember on its proximal end. Alternatively, such a coupling member mayalso be used with a guidewire including a coupling member, such as ashaped region.

FIG. 370 shows an alternative embodiment of a guidewire coupling member,which includes two opposing cams 370310 that rotate toward one another(curved arrows) to grip and hold a guidewire 370312. As with theprevious embodiment, this coupling member may be used, in variousembodiments, either with a guidewire having shaped proximal end or anunshaped guidewire 370312.

In the variations illustrated in FIGS. 369 and 370 only one couplingmember may be used. For example, a guidewire coupling member on thesurgical device may couple with the proximal end of the guidewire, evenif the guidewire does not include an additional coupling member (e.g., ashaped region or other coupling member).

Referring now to FIGS. 371A-371C, in another embodiment, a guidewirecoupling member 371320 (shown in top view) may include three movablerollers 371322. In an open position, as in FIG. 371A, rollers 371322 maybe arrayed to allow a guidewire 371324 to pass through them. Rollers371322 may be moved, relative to one another (solid-tipped arrows), topartially constrain guidewire 371324 (FIG. 371B) or to completelyconstrain guidewire 371324 (FIG. 371C). Rollers 371322 may be moved backto the open position (FIG. 371A) to release guidewire 371324.

In an alternative embodiment, and referring now to FIGS. 372A-372C, aguidewire coupling member 372330 may include a multi-piece cone 372332having a core 372334 with a textured inner surface 372335, and astationary portion 372336 having a receptacle 372338 for receiving cone372332. In an open position, as in FIG. 372B, the two halves of cone372332 are separated and not wedged into receptacle 372338, so that aguidewire 372339 may be passed through core 372334. Cone 372332 may bemoved to a closed position, as in FIG. 372C, to grip guidewire 372339with textured surface 372335 and prevent guidewire 372339 from movingfurther through core 372334. In one embodiment, for example, asguidewire 372339 moves through core 372334, it may generate frictionwith textured surface 372335 and thus pull cone 372332 into receptacle.As with several previous embodiments, guidewire 372339 may eitherinclude a proximal shaped member or may not include such a member, invarious embodiments.

With reference now to FIG. 373, in another embodiment, a guidewirecoupling member 373340 may include a flat anvil 373342 and one or morestationary portions 373344. Anvil may be moved (hollow-tipped arrow) topinch a guidewire 373344 between itself and stationary portion 373344.

In an alternative embodiment, shown in FIG. 374, a guidewire couplingmember 374350 may include a corner-pinch mechanism 374352 and one ormore stationary portion 374354. Mechanism 374352 may be advanced(hollow-tipped arrow) to pinch guidewire 374356 against stationarymember 374354 and thus prevent it from moving further through couplingdevice 374350.

Referring to FIG. 375, another embodiment of a guidewire coupling member375360 is shown, which includes an eccentric cam 375362 that rotates(hollow-tipped arrow) to pinch a guidewire 375366 between itself and astationary portion 375364.

In another embodiment, with reference to FIGS. 378A and 378B, aguidewire coupling member 378390 may include multiple spools 378392,through which a guidewire 378394 may pass, until a shaped member 378396on one end of guidewire 378394 gets caught. FIG. 378B shows couplingmember 378390 attached with an upper surface of a surgical device distalend 378391.

In yet another embodiment, and with reference now to FIGS. 379A and379B, a guidewire coupling member 379400 may include a semi-circularribbon 379402 having two apertures 379404. With this embodiment ofcoupling member 379400 (as well as other embodiment described herein), atextured guidewire 379406 may be used. As textured guidewire 379406passes through apertures 379404, friction caused by the textured surface379407 causes ribbon 379402 to flatten (FIG. 379B), thus trappingguidewire 379406 in apertures 379404. Ribbon 379402 may be made of metalor any other suitable material, examples of which have been listedpreviously.

Referring to FIG. 380, another alternative embodiment is shown, in whicha guidewire coupling member 380410 includes a folded ribbon 380412having multiple apertures 380414. Ribbon 380412 may flatten as atextured guidewire 380416 passes through it, thus causing apertures totrap guidewire 380416.

Another embodiment of a guidewire coupling member 381420 is shown inFIG. 381. In this embodiment, coupling member 381420 includes a curvedribbon 381422 with multiple apertures 381424. Ribbon 381422 may flattento constrain a guidewire 381426 in apertures 381424, as with thepreviously described embodiments. Some embodiments of such ribbon-shapedcoupling members 379400, 380410, 381420 may function with a non-texturedguidewire as well as, or in place of, a textured guidewire.

Referring to FIG. 382, in another embodiment, a guidewire couplingmember 382430 for removably coupling with a guidewire 382438 may includea stationary portion 382432 and a movable portion 382434. Movableportion 382434 may include multiple contact members 382436 or lockingedges, configured to hold guidewire 382438 when movable portion 382434is pushed against it (hollow-tipped arrows). Movable portion 382434 maybe moved using any suitable technique or means in various embodiments.Contact members 382436 generally press guidewire 382438 againststationary portion 382432 such that it will not move through couplingmember 382430 when pulled (solid-tipped arrow), thus allowing a devicecoupled with coupling member 382430 to be pulled using guidewire 382438.

In another embodiment, and with reference now to FIG. 383, a guidewirecoupling member 383440 may include a stationary portion 383442 and amovable portion 383444, each of which has a roughened surface 383446facing one another. Movable portion 383444 may be moved towardstationary portion 383442 (hollow-tipped arrows) to trap guidewire383446 in between, thus preventing guidewire 383446 from moving throughcoupling member 383440 and thus allowing a device coupled with couplingmember 383440 to be pulled via guidewire 383448.

Turning to FIGS. 384A-384D, several alternative embodiments of aguidewire for use with various embodiments of a guidewire couplingmember and guidewire system are shown. In some embodiments of aguidewire system, any of a number of currently available guidewires maybe used. In other embodiments, a textured guidewire without a shapedmember on either end may be used. Each of the embodiments shown in FIGS.384A-384D, by contrast, has some kind of shaped member on a proximal endof the guidewire for coupling with a guidewire coupling member and somekind of sharpened or otherwise shaped distal tip for facilitatingpassage of the guidewire through tissue.

In various embodiments, guidewires may comprise a solid wire, a braidedwire, a core with an outer covering or the like, and may be made of anysuitable material. For example, in one embodiment, a guidewire may bemade of Nitinol. In various alternative embodiments, guidewires may bemade from any of a number of metals, polymers, ceramics, or compositesthereof. Suitable metals, for example, may include but are not limitedto stainless steel, nickel-titanium alloy, tungsten carbide alloy, orcobalt-chromium alloy, for example, Elgiloy™ (Elgin Specialty Metals,Elgin, Ill., USA), Conichrome™ (Carpenter Technology, Reading, Pa.,USA), or Phynox™ (Imphy SA, Paris, France). In some embodiments,materials for guidewires or for portions or coatings of guidewires maybe chosen for their electrically conductive or thermally resistiveproperties. Suitable polymers include but are not limited to nylon,polyester, Dacron™, polyethylene, acetal, Delrin™ (DuPont, Wilmington,Del.), polycarbonate, nylon, polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK). In some embodiments, polymers may beglass-filled to add strength and stiffness. Ceramics may include but arenot limited to aluminas, zirconias, and carbides.

In the embodiment shown in FIG. 384A, the guidewire 384180 includes adevice coupling member that is configured as a ball-like shaped member384182 at the proximal end and a pointed distal tip 384184. As with allthe following exemplary embodiments, shaped member 384182 may be eithera separate piece attached to guidewire 384180 by welding or other meansor may be a proximal end of guidewire 384180, formed into shaped member384182. FIG. 384B shows a guidewire 384186 with a cylindrical shapedmember 384188 and a beveled distal tip 384190. FIG. 384C shows aguidewire 384192 with a pyramidal shaped member 384194 and adouble-beveled distal tip 384196. FIG. 384D shows a guidewire 384198with a cubic shaped member 384200 and a threaded distal tip 384202. Inother variations (e.g., refer to FIGS. 376A-376B) the proximal end ofthe guidewire may include a hook for coupling with a guidewire couple.

In alternative embodiments, any of the shaped members384182,384188,384194, 384200 may be combined with any of the distal tips384184, 384190, 384196, 384202. In yet other alternative embodiments,the shaped members and/or distal tips may have other shapes and/orsizes. Thus, the embodiments shown in FIGS. 384A-384D are providedprimarily for exemplary purposes.

Referring now to FIGS. 385A and 385B, another embodiment of a guidewire385204 may include a drill-shaped distal tip 385206 with a cutting edge385208. Such a drill-shaped tip 385206 may facilitate passage ofguidewire 385204 through tissue, as shown in FIG. 385B. Guidewire 385204may be advanced through a probe 385210 and through tissue (not shown) bysimultaneously pushing (solid-tipped, straight arrows) and twisting(hollow-tipped, curved arrows) guidewire 385204 from its proximal end.Drill-shaped tip 385206 may facilitate passage of guidewire 385204through tissue by acting as a drill.

FIGS. 388 and 389A-389C illustrate another variation of an exchangesystem including a guidewire and a surgical device having a distalguidewire coupling exchange tip (“Rx” or exchange tip). In thisvariation the guidewire coupling member is configured to engage theproximal end of the guidewire, which is configured as a device couplingmember having a cylindrical-shaped member. FIGS. 389A and 389Billustrate the coupling of the proximal end of the guidewire and thedistal end of the device. In this variation, the two coupling regionsare configured to lock when engaged, so that they may not be separatedwithout the proper orientation and/or application of force. Asillustrated in FIG. 389C, the opening in the guidewire coupling memberhas a diameter “A” that is greater than the diameter of the short axis(“B”) of the distal end of the coupling member on the guidewire, butsmaller than the longitudinal axis (“C”) of the device coupling memberon the guidewire. When the device coupling member of the guidewire isinserted in the opening in the guidewire coupling member of the device,and tension is applied (pulling the guidewire distal to the couplingmember so that it extends in the slot of the guidewire coupling member),the guidewire and the device are locked together, and cannot beseparated (even when tension is removed) without properly orienting thetwo so that the small diameter (“B”) of the coupling member can exit theopening of the guidewire coupling member.

FIGS. 390A-390D illustrate a very similar variation, in which the devicecoupling member on the proximal end of the guidewire may be permanentlysecured in the guidewire coupling member. In this example, the devicecoupling member of the guidewire has a conical, triangular or pyramidalshape in which the proximal end tapers distally so that as the proximalend of the guidewire is pulled into the guidewire coupling member of thesurgical device, it become wedged and locked into the coupling member,as illustrated in FIG. 390D. Other variations of locking couplingmembers may be used, including releasably and permanently lockingmembers.

FIGS. 391A-391C illustrate another variation of a locking guidewireexchange system. In this variation the proximal end of the guidewire isconfigured as a loop or eyelet, and the distal end of the surgicaldevice is configured as a hook having a progressively thickercross-section. The very proximal end of the hook may be flanged awayfrom the body slightly, allowing the loop or eyelet to more easilyengage the hook. The thinner region at the proximal end may be moreflexible, so that the look or eyelet can be pulled into the hook regionby deflecting the thinner portion away from the longitudinal axissufficiently to allow the loop to pass into the hook region. Thus, thehook may be referred to as a “spring clip” hook. The guidewire may bereleased from the device by applying appropriate force to pull the loopout of the spring clip hook.

Another locking variation of a guidewire exchange system is shown inFIGS. 392A-392C. In this example, the guidewire coupling member on thedevice is configured as a coil or spring into which the guidewire may beinserted. The walls of the spring region may be tapered slightly toguide insertion. Pushing the guidewire into the coupling member mayexpand the spring slightly, whereas applying a tensioning force (e.g.,by pulling on either or both the proximal end of the device and distalend of the guidewire) will tighten the connection between the guidewireand the device. In some variations the guidewire also include a couplingmember which may be one or more regions (e.g., rings, ridges, bumps,etc.) that can fit between the loops or coils of the guidewire couplingmember on the device.

FIGS. 393A-393C, 394A-394B, and 395A-395C illustrate other variations oflocking or lockable guidewire exchange systems. In all of these exchangesystems the guidewire may be secured to a first surgical device, andtension may be applied (e.g., to pull the device into position using theguidewire, and/or to urge the device against the target tissue). Thedevices may then be de-coupled from the guidewire (e.g., after thedevices have been removed from the subject while leaving the guidewirein place), and another device may be coupled to the guidewire andpositioned by pulling the guidewire and/or used to urge the deviceagainst the target tissue.

For example, FIG. 393A-393C illustrate a guidewire having a loop oreyelet at the proximal end coupling with a guidewire coupling region ofa surgical device that is configured as a clasp. The clasp includes jawsthat may move to close over the eyelet, securing it on a hook or post inthe guidewire coupling region. In the example shown in FIGS. 394A and394B, the proximal end of the guidewire is threaded and may be screwedinto the guidewire coupling member of a surgical device, shown in crosssection in FIG. 394B. Finally, in FIGS. 395A-395C the guidewire couplingmember of a surgical device includes a sliding lock may be used tosecure a hinged jaw closed over the proximal end of a guidewire. Thelock may be slid proximally to unlock the hinged jaw and release theguidewire.

FIGS. 396A and 396B illustrate another variation of a spring-lockingguidewire coupling region on a surgical device that mates with thedevice coupling region on a guidewire. In this example, a spring in theguidewire coupling member pushes one or more wedge locks distally. Thespring and wedge locks can be displaced by pushing the proximal end ofthe guidewire into the coupling member proximally, but pulling distallyonly provides additional force to lock the guidewire in the couplingmember. A lock release mechanism (e.g., pulling the spring or wedgelocks proximally) may be included to allow release of the guidewire.

With reference to FIG. 386A, in some embodiments, a guidewire system mayinclude a guidewire handle 386220 for grasping a guidewire outside thepatient. Such a guidewire handle 386220 may include, for example, aguidewire clamping mechanism 386222 housed in a central, longitudinalbore 386221 of handle 386220 and including a central guidewire aperture386223. Handle 386220 may also include a lock lever 386224 fortightening clamping mechanism 386222 around a guidewire. At some pointsin the present application, handles similar to handle 386220 arereferred to as “distal handles,” and handles coupled with various tissuemodification devices are referred to as “proximal handles.” These terms,“distal” and “proximal,” are generally used to distinguish the two typesof handles and to denote that one is more proximal than the other,during use, to a first incision or entry point into a patient, throughwhich a guidewire system is placed and then used to pull a tissuemodification device into position in the patient. “Distal” and“proximal,” however, are used merely for clarification and do not referto the relation of any device to specific anatomical structures, theposition of a physician/user of the described devices/systems, or thelike. Thus, in various embodiments, either type of handle may be“distal” or “proximal” relative to various structures, users or thelike. For the purposes of FIGS. 386A and 386B, the embodiment isdescribed as guidewire handle 386220, denoting its function of holding aguidewire.

FIG. 386B provides an exploded view guidewire handle 386220. A handlebody 386225 may be made of any suitable material and have any desiredshape and size. In various alternative embodiments, for example, handlebody 386220 may be made from any of a number of metals, polymers,ceramics, or composites thereof. Suitable metals, for example, mayinclude but are not limited to stainless steel, nickel-titanium alloy,tungsten carbide alloy, or cobalt-chromium alloy, for example, Elgiloy™(Elgin Specialty Metals, Elgin, Ill., USA), Conichrome™ (CarpenterTechnology, Reading, Pa., USA), or Phynox™ (Imphy SA, Paris, France).Suitable polymers include but are not limited to nylon, polyester,Dacron™, polyethylene, acetal, Delrin™ (DuPont, Wilmington, Del.),polycarbonate, nylon, polyetheretherketone (PEEK), andpolyetherketoneketone (PEKK). Ceramics may include but are not limitedto aluminas, zirconias, and carbides.

Clamping mechanism 386222 may include, for example, a snap ring 386226,a keeper washer 386228, a flat anvil 386230, and a cage barrel 386232,all of which fit within central bore 386221 of handle body 386225. Locklever 386224 may be coupled with a pinch screw 386234 and a shoulderscrew 386236. When lock lever 386224 is turned in one direction, itpushes shoulder screw 386236 against clamping mechanism 386222 to causemechanism 386222 to clamp down on a guidewire. Lock lever 386224 may beturned in an opposite direction to loosen clamping mechanism 386222,thus allowing a guidewire to be introduced into or release from centralguidewire aperture 386223.

FIGS. 387A-387B illustrate one method of using an exchange system asdescribed. For example, FIG. 387A shows a spinal region including aneural foramen into which a cannulated probe (curve cannula) has beeninserted. In general, the guidewire is inserted into the tissue (e.g.,through a neural foramen) so that the pathway through the tissueincludes at least one (or only one) bend or curve in which the targettissue is positioned within the radius of the curve. The guidewire maybe positioned by one or more access devices. For example, FIG. 387Ashows positioning of a guidewire using an access cannula having anintegrated curved inner cannula slidably disposed within the outercannula. The inner curved member is extended from the distal end of theaccess cannula into the foramen and around the target tissue, as shown.A guidewire may then be inserted through it, so that a distal end of theguidewire (which may be sharp) extends from the patient. Either or boththe cannula and the curved inner member may also include a neurallocalization electrode or electrodes so that the guidewire can bepositioned away from the nerve. The access cannula can then be retractedand removed from the patient, leaving the guidewire behind. Asillustrated in FIGS. 387B and 387C, the guidewire may then be used (asdescribed in detail above) to pull a surgical device (e.g., a cuttingdevice, etc.) through the body so that it is positioned relative to thetarget tissue. For example, the proximal end of the cannula, initiallyprotruding from the patient, may be coupled to a surgical device, asdescribed above. As shown in FIG. 387C, the distal end of the guidewirecan then be pulled to draw the surgical device through the patient untilit is positioned as desired relative to the target tissue. In somevariations the positioning may be confirmed. Positioning may beconfirmed by one or more of a direct visualization technique, feel(e.g., tactile feedback on the guidewire and/or surgical device),sensors on the surgical device or guidewire, depth markers on theguidewire or surgical device, or the like.

Once in position, tension may be applied to the surgical device. Forexample, in some variations the guidewire remains at least partially inthe patient and attached to the surgical device. Tension may be appliedby pulling distally on the guidewire and proximally on the surgicaldevice, to urge the surgical device against the target tissue. Thesurgical device may then be moved (e.g., back and forth across thetarget tissue) to mechanically actuate the surgical device, or it may beotherwise actuated, as described previously. After treatment of thetissue with this first surgical device, the device may be withdrawn fromthe patient. For example, the device may be withdrawn by pulling itproximally out of the patient, until the proximal end of the guidewireis again outside of the patient.

The surgical device can then be exchanged on the guidewire. For example,the proximal end of the guidewire may then be de-coupled from thesurgical device, and another surgical device may be coupled, aspreviously described. The surgical device can again be positionedadjacent to the target tissue, and the device can be urged against thetarget tissue. This procedure may be repeated as often as necessaryuntil the target tissue has been treated to the desired level. Asmentioned above, any appropriate surgical device may be used an appliedin this way, including (but not limited to) decompression devices,measuring devices (balloons, sounds, etc.), catheters or other devicesfor suction and irrigation, and devices for delivering active agents(i.e., hemostatic agents such as Thrombin, steroids, or other drugs),bone wax, etc. Implants may also be positioned by pulling then throughthe subject using the guidewire.

Once the procedure is complete, the guidewire may be removed from thesubject.

Although various illustrative embodiments are described above, any of anumber of changes may be made to various embodiments without departingfrom the scope of the invention as described by the claims. For example,the order in which various described method steps are performed mayoften be changed in alternative embodiments, and in other alternativeembodiments one or more method steps may be skipped altogether. Optionalfeatures of various device and system embodiments may be included insome embodiments and not in others. Therefore, the foregoing descriptionis provided primarily for exemplary purposes and should not beinterpreted to limit the scope of the invention as it is set forth inthe claims.

We claim:
 1. A method of treating a patient, the method comprising:advancing a distal end of a guidewire into the patient's body from afirst site, advancing adjacent to a target tissue, and out of the bodyfrom a second site, while maintaining a proximal end of the guidewireoutside the body at the first site; coupling an end of the guidewire onor near a distal end of a first surgical device outside of the body byinserting the end of the guidewire into a channel at or near the distalend of the first surgical device; pulling the guidewire to guide thefirst surgical device adjacent to the target tissue; and withdrawing thefirst surgical device and end of the guidewire from the patient whilemaintaining the guidewire within the body and de-coupling the end of theguidewire from the surgical device; coupling the end of the guidewire onor near a distal end of a second surgical device outside of the body byinserting the end of the guidewire into a channel at or near the distalend of the second surgical device.
 2. The method of claim 1, whereinadvancing the distal end of the guidewire comprises pushing a sharpdistal end of the guidewire through the tissue, wherein the guidewirecuts the tissue as it is advanced.
 3. The method of claim 1, whereincoupling the end of the guidewire on or near the distal end of thesurgical device comprises coupling the end of the guidewire to the firstor second surgical device with at least one coupling member.
 4. Themethod of claim 1, wherein coupling the end of the guidewire on or nearthe distal end of the first surgical device comprises engaging a regionat the distal end of the guidewire that is larger than a more proximalregion of the guidewire with a channel on or in the surgical device. 5.The method of claim 1, wherein de-coupling the end of the guidewire fromthe first surgical device comprises rotating the end of the guidewire,the distal end of the first surgical device, or both, to release ashaped member from the channel.
 6. The method of claim 1, furthercomprising urging the second surgical device against the target tissueby applying tension to either or both the portion of the second surgicaldevice extending from the first site and the guidewire extending fromthe second site.
 7. The method of claim 1, further comprising performinga surgical procedure on the target tissue using the surgical device. 8.The method of claim 7, wherein the step of performing a surgicalprocedure comprises reciprocating the surgical device by pulling oneither or both of the second surgical device extending from the firstsite and the guidewire extending from the second site.
 9. A method forguiding at least a portion of a surgical device to a desired position ina patient's body, the method comprising: advancing a sharp distal end ofa guidewire into the patient's body, and out of the body, whilemaintaining a proximal end of the guidewire outside the body, whereinthe sharp distal end cuts through tissues of the patient's body;coupling the proximal end of the guidewire with at least one couplingmember on or near a distal end of a first surgical device outside of thebody by inserting the guidewire into a channel at or near the distal endof the first surgical device; pulling the distal end of the guidewire toguide at least a portion of the surgical device to a desired positionadjacent to the target tissue; withdrawing the surgical device anddistal end of the guidewire proximally from the patient whilemaintaining the guidewire within the body and de-coupling the proximalend of the guidewire from the surgical device; coupling the proximal endof the guidewire with at least one coupling member on or near a distalend of a second surgical device outside of the body; pulling the distalend of the guidewire to guide at least a portion of an abrasive surfaceof the second surgical device to a desired position adjacent to thetarget tissue.
 10. A method for performing a procedure on a targettissue in a patient's body, the method comprising: coupling a proximalend of a guidewire with a coupling member on or near a distal end of afirst surgical device outside of the body by inserting the proximal endof the guidewire into or near the distal end of the first surgicaldevice; pulling a distal end of the guidewire to guide at least aportion of the first surgical device to a desired position in thepatient's body; performing a procedure on the target tissue byreciprocating the surgical device by applying tension to both a portionof the guidewire outside of the body and a proximal portion of thesurgical device; withdrawing the surgical device and proximal end of theguidewire from the patient leaving the guidewire within the patient;de-coupling the proximal end of the guidewire from the surgical device,and coupling the proximal end of the guidewire on or near a distal endof a second surgical device outside of the body; and pulling a distalend of the guidewire to guide at least a portion of the second surgicaldevice to a desired position in the patient's body, such that anabrasive portion of the second surgical device faces the target tissue.11. The method of claim 10, further comprising coupling the proximal endof the guidewire on or near the distal end of the first surgical deviceby coupling the proximal end of the guidewire to the first surgicaldevice with at least one coupling member.
 12. The method of claim 10,further comprising coupling the proximal end of the guidewire on or nearthe distal end of the first surgical device by engaging a guidewirecoupling member on the first surgical device with the proximal end ofthe guidewire.
 13. The method of claim 10, wherein de-coupling the endof the guidewire from the first surgical device further comprisesreleasing a shaped member from a channel in the first surgical device.